diff --git a/packages/sts-like-viewer/src/gameobjects/InventoryItemContainer.ts b/packages/sts-like-viewer/src/gameobjects/InventoryItemContainer.ts
new file mode 100644
index 0000000..61b3ef8
--- /dev/null
+++ b/packages/sts-like-viewer/src/gameobjects/InventoryItemContainer.ts
@@ -0,0 +1,173 @@
+import Phaser from "phaser";
+import { dragDropEventEffect, DragDropEventType } from "boardgame-phaser";
+import { GRID_CONFIG, ITEM_COLORS } from "@/config";
+import {
+  IDENTITY_TRANSFORM,
+  ParsedShape,
+  Transform2D,
+  transformShape,
+  type GameItem,
+  type GameItemMeta,
+  type InventoryItem,
+} from "boardgame-core/samples/slay-the-spire-like";
+import { computed, signal, Signal } from "@preact/signals-core";
+import { DisposableBag } from "../../../framework/dist";
+
+export interface InventoryItemContainerCallbacks {
+  onMoveItem: (itemId: string, newX: number, newY: number) => boolean;
+}
+
+export class InventoryItemContainer extends Phaser.GameObjects.Container {
+  private item: Signal<GameItem | undefined>;
+
+  constructor(
+    scene: Phaser.Scene,
+    private gridOffsetX: number,
+    private gridOffsetY: number,
+    private callbacks: InventoryItemContainerCallbacks,
+  ) {
+    super(scene, gridOffsetX, gridOffsetY);
+    scene.add.existing(this);
+    this.setupInteractive();
+
+    const graphics = this.scene.add.graphics();
+    const label = this.scene.add.text(
+      GRID_CONFIG.VIEWER_CELL_SIZE / 2,
+      GRID_CONFIG.VIEWER_CELL_SIZE / 2,
+      "",
+      GRID_CONFIG.ITEM_NAME_STYLE,
+    );
+    this.add([graphics, label]);
+
+    this.item = signal();
+
+    const disposables = new DisposableBag(this);
+
+    const itemName = computed(() => {
+      const item = this.item.value;
+      return item?.meta?.itemData.name ?? item?.id ?? "";
+    });
+    disposables.addEffect(() => {
+      label.setText(itemName.value);
+    });
+
+    const shape = computed(() => {
+      return this.item.value?.shape;
+    });
+    const color = computed(() => {
+      return this.getItemColor(this.item.value?.id ?? "");
+    });
+    disposables.addEffect(() => {
+      graphics.clear();
+      if (!shape.value) return;
+      this.renderGraphics(graphics, shape.value, color.value);
+    });
+
+    const transform = computed(() => {
+      return this.item.value?.transform;
+    });
+    disposables.addEffect(() => {
+      if (!transform.value) return;
+      this.snapBack(transform.value);
+    });
+  }
+
+  setItem(item: GameItem) {
+    this.item.value = item;
+  }
+
+  renderGraphics(
+    graphics: Phaser.GameObjects.Graphics,
+    shape: ParsedShape,
+    itemColor: number,
+  ): void {
+    const cells = transformShape(shape, IDENTITY_TRANSFORM);
+    for (const cell of cells) {
+      const localX = (cell.x - cells[0].x) * GRID_CONFIG.VIEWER_CELL_SIZE;
+      const localY = (cell.y - cells[0].y) * GRID_CONFIG.VIEWER_CELL_SIZE;
+
+      graphics.fillStyle(itemColor);
+      graphics.fillRect(
+        localX + 2,
+        localY + 2,
+        GRID_CONFIG.VIEWER_CELL_SIZE - 4,
+        GRID_CONFIG.VIEWER_CELL_SIZE - 4,
+      );
+    }
+
+    this.setSize(
+      GRID_CONFIG.VIEWER_CELL_SIZE * shape.width,
+      GRID_CONFIG.VIEWER_CELL_SIZE * shape.height,
+    );
+  }
+
+  private getItemColor(itemId: string): number {
+    const hash = itemId.split("").reduce((acc, c) => acc + c.charCodeAt(0), 0);
+    return ITEM_COLORS[hash % ITEM_COLORS.length];
+  }
+
+  private setupInteractive(): void {
+    this.setScrollFactor(0);
+    this.setInteractive({ useHandCursor: true });
+
+    let startX = 0;
+    let startY = 0;
+    dragDropEventEffect(this, (event) => {
+      if (event.type === DragDropEventType.DOWN) {
+        startX = this.x;
+        startY = this.y;
+        this.setAlpha(0.7);
+      } else if (event.type === DragDropEventType.MOVE) {
+        this.x = startX + event.deltaX;
+        this.y = startY + event.deltaY;
+      } else if (event.type === DragDropEventType.UP) {
+        this.setAlpha(1);
+        if (!this.handleDragEnd()) {
+          this.x = startX;
+          this.y = startY;
+        }
+        startX = startY = 0;
+      }
+    });
+  }
+
+  private handleDragEnd(): boolean {
+    const item = this.item.value;
+    if (!item) return false;
+    const itemId = item.id;
+
+    const cellSize = GRID_CONFIG.VIEWER_CELL_SIZE;
+    const shapeWidth = item.shape?.width ?? 1;
+    const shapeHeight = item.shape?.height ?? 1;
+
+    const x = this.x - this.gridOffsetX;
+    const y = this.y - this.gridOffsetY;
+    const targetX = Math.round((x - cellSize / 2) / cellSize);
+    const targetY = Math.round((y - cellSize / 2) / cellSize);
+
+    const clampedX = Math.max(0, Math.min(targetX, 10 - shapeWidth));
+    const clampedY = Math.max(0, Math.min(targetY, 10 - shapeHeight));
+
+    if (
+      clampedX !== item.transform.offset.x ||
+      clampedY !== item.transform.offset.y
+    ) {
+      return this.callbacks.onMoveItem(itemId, clampedX, clampedY);
+    }
+    return false;
+  }
+
+  private snapBack(transform: Transform2D): void {
+    const { x, y } = transform.offset;
+    const targetX = this.gridOffsetX + x * GRID_CONFIG.VIEWER_CELL_SIZE;
+    const targetY = this.gridOffsetY + y * GRID_CONFIG.VIEWER_CELL_SIZE;
+
+    this.scene.tweens.add({
+      targets: this,
+      x: targetX,
+      y: targetY,
+      duration: 150,
+      ease: "Power2",
+    });
+  }
+}
diff --git a/packages/sts-like-viewer/src/gameobjects/InventoryItemSpawner.ts b/packages/sts-like-viewer/src/gameobjects/InventoryItemSpawner.ts
new file mode 100644
index 0000000..e32df2e
--- /dev/null
+++ b/packages/sts-like-viewer/src/gameobjects/InventoryItemSpawner.ts
@@ -0,0 +1,86 @@
+import Phaser from "phaser";
+import type { Spawner } from "boardgame-phaser";
+import type {
+  GameItemMeta,
+  InventoryItem,
+} from "boardgame-core/samples/slay-the-spire-like";
+import type { InventorySignal } from "@/state/inventory";
+import { spawnEffect } from "boardgame-phaser";
+import { InventoryItemContainer } from "./InventoryItemContainer";
+import type { InventoryItemContainerCallbacks } from "./InventoryItemContainer";
+
+export interface InventoryItemSpawnerCallbacks extends InventoryItemContainerCallbacks {}
+
+export class InventoryItemSpawner implements Spawner<
+  [string, InventoryItem<GameItemMeta>],
+  InventoryItemContainer
+> {
+  constructor(
+    private scene: Phaser.Scene,
+    private inventorySignal: InventorySignal,
+    private gridOffsetX: number,
+    private gridOffsetY: number,
+    private callbacks: InventoryItemSpawnerCallbacks,
+  ) {}
+
+  *getData(): Iterable<[string, InventoryItem<GameItemMeta>]> {
+    const inventory = this.inventorySignal.value;
+    yield* inventory.items.entries();
+  }
+
+  getKey(entry: [string, InventoryItem<GameItemMeta>]): string {
+    return entry[0];
+  }
+
+  onSpawn(
+    entry: [string, InventoryItem<GameItemMeta>],
+  ): InventoryItemContainer | null {
+    const [itemId, item] = entry;
+
+    const container = new InventoryItemContainer(
+      this.scene,
+      this.gridOffsetX,
+      this.gridOffsetY,
+      {
+        onMoveItem: (id, newX, newY) => {
+          return this.callbacks.onMoveItem(id, newX, newY);
+        },
+      },
+    );
+
+    container.setItem(item);
+    return container;
+  }
+
+  onUpdate(
+    entry: [string, InventoryItem<GameItemMeta>],
+    container: InventoryItemContainer,
+  ): void {
+    const [itemId, item] = entry;
+
+    container.setItem(item);
+  }
+
+  onDespawn(container: InventoryItemContainer): void {
+    // TODO: add tween
+    container.destroy();
+  }
+}
+
+export function createInventoryItemSpawner(
+  scene: Phaser.Scene,
+  inventorySignal: InventorySignal,
+  gridOffsetX: number,
+  gridOffsetY: number,
+  callbacks: InventoryItemSpawnerCallbacks,
+) {
+  return spawnEffect(
+    new InventoryItemSpawner(
+      scene,
+      inventorySignal,
+      gridOffsetX,
+      gridOffsetY,
+      callbacks,
+    ),
+  );
+}
diff --git a/packages/sts-like-viewer/src/scenes/InventoryItemSpawner.ts b/packages/sts-like-viewer/src/scenes/InventoryItemSpawner.ts
deleted file mode 100644
index 57c2eb0..0000000
--- a/packages/sts-like-viewer/src/scenes/InventoryItemSpawner.ts
+++ /dev/null
@@ -1,270 +0,0 @@
-import Phaser from "phaser";
-import {
-  spawnEffect,
-  dragDropEventEffect,
-  DragDropEventType,
-  type Spawner,
-} from "boardgame-phaser";
-import { GRID_CONFIG, ITEM_COLORS } from "@/config";
-import type {
-  GameItemMeta,
-  InventoryItem,
-} from "boardgame-core/samples/slay-the-spire-like";
-import type { InventorySignal } from "@/state/inventory";
-
-export interface InventoryItemSpawnerCallbacks {
-  onMoveItem: (itemId: string, newX: number, newY: number) => void;
-}
-
-export class InventoryItemSpawner implements Spawner<
-  [string, InventoryItem<GameItemMeta>],
-  Phaser.GameObjects.Container
-> {
-  private dragState: {
-    itemId: string;
-    startX: number;
-    startY: number;
-    container: Phaser.GameObjects.Container;
-  } | null = null;
-
-  constructor(
-    private scene: Phaser.Scene,
-    private inventorySignal: InventorySignal,
-    private gridOffsetX: number,
-    private gridOffsetY: number,
-    private callbacks: InventoryItemSpawnerCallbacks,
-  ) {}
-
-  *getData(): Iterable<[string, InventoryItem<GameItemMeta>]> {
-    const inventory = this.inventorySignal.value;
-    yield* inventory.items.entries();
-  }
-
-  getKey(entry: [string, InventoryItem<GameItemMeta>]): string {
-    return entry[0];
-  }
-
-  private getCells(
-    item: InventoryItem<GameItemMeta>,
-  ): { x: number; y: number }[] {
-    const cells: { x: number; y: number }[] = [];
-    const shape = item.shape;
-    const transform = item.transform;
-
-    for (let y = 0; y < shape.height; y++) {
-      for (let x = 0; x < shape.width; x++) {
-        if (shape.grid[y]?.[x]) {
-          const finalX = x + transform.offset.x;
-          const finalY = y + transform.offset.y;
-          cells.push({ x: finalX, y: finalY });
-        }
-      }
-    }
-    return cells;
-  }
-
-  private getItemColor(itemId: string): number {
-    const hash = itemId.split("").reduce((acc, c) => acc + c.charCodeAt(0), 0);
-    return ITEM_COLORS[hash % ITEM_COLORS.length];
-  }
-
-  onSpawn(
-    entry: [string, InventoryItem<GameItemMeta>],
-  ): Phaser.GameObjects.Container | null {
-    const [itemId, item] = entry;
-    const container = this.scene.add.container(0, 0);
-    const cells = this.getCells(item);
-
-    const itemColor = this.getItemColor(itemId);
-    const graphics = this.scene.add.graphics();
-
-    // Draw graphics in container-local coordinates (container is at firstCell position)
-    for (const cell of cells) {
-      // Local coordinates relative to container position
-      const localX = (cell.x - cells[0].x) * GRID_CONFIG.VIEWER_CELL_SIZE;
-      const localY = (cell.y - cells[0].y) * GRID_CONFIG.VIEWER_CELL_SIZE;
-
-      graphics.fillStyle(itemColor);
-      graphics.fillRect(
-        localX + 2,
-        localY + 2,
-        GRID_CONFIG.VIEWER_CELL_SIZE - 4,
-        GRID_CONFIG.VIEWER_CELL_SIZE - 4,
-      );
-    }
-
-    if (cells.length > 0) {
-      const itemName = item.meta?.itemData.name ?? itemId;
-
-      // Text is centered in the first cell, relative to container
-      const textX = GRID_CONFIG.VIEWER_CELL_SIZE / 2;
-      const textY = GRID_CONFIG.VIEWER_CELL_SIZE / 2;
-
-      const text = this.scene.add.text(
-        textX,
-        textY,
-        itemName,
-        GRID_CONFIG.ITEM_NAME_STYLE,
-      );
-      text.setOrigin(0.5);
-
-      container.add([graphics, text]);
-
-      // Position container at the first cell's world position
-      const worldX =
-        this.gridOffsetX + cells[0].x * GRID_CONFIG.VIEWER_CELL_SIZE;
-      const worldY =
-        this.gridOffsetY + cells[0].y * GRID_CONFIG.VIEWER_CELL_SIZE;
-      container.setPosition(worldX, worldY);
-    } else {
-      container.add(graphics);
-    }
-
-    // Make container interactive for drag-and-drop
-    container.setInteractive(
-      new Phaser.Geom.Rectangle(
-        0,
-        0,
-        GRID_CONFIG.VIEWER_CELL_SIZE,
-        GRID_CONFIG.VIEWER_CELL_SIZE,
-      ),
-      Phaser.Geom.Rectangle.Contains,
-    );
-    container.setScrollFactor(0);
-    container.setSize(
-      GRID_CONFIG.VIEWER_CELL_SIZE * (item.shape?.width ?? 1),
-      GRID_CONFIG.VIEWER_CELL_SIZE * (item.shape?.height ?? 1),
-    );
-
-    // Setup drag handling
-    dragDropEventEffect(container, (event) => {
-      if (event.type === DragDropEventType.DOWN) {
-        // Start drag
-        this.dragState = {
-          itemId,
-          startX: container.x,
-          startY: container.y,
-          container,
-        };
-        container.setAlpha(0.7);
-      } else if (event.type === DragDropEventType.MOVE) {
-        // Update drag position
-        if (this.dragState?.itemId === itemId) {
-          container.x = this.dragState.startX + event.deltaX;
-          container.y = this.dragState.startY + event.deltaY;
-        }
-      } else if (event.type === DragDropEventType.UP) {
-        // End drag
-        if (this.dragState?.itemId === itemId) {
-          container.setAlpha(1);
-          this.handleDragEnd(itemId, container);
-          this.dragState = null;
-        }
-      }
-    });
-
-    return container;
-  }
-
-  private handleDragEnd(
-    itemId: string,
-    container: Phaser.GameObjects.Container,
-  ): void {
-    const inventory = this.inventorySignal.value;
-    const item = inventory.items.get(itemId);
-    if (!item) return;
-
-    const cellSize = GRID_CONFIG.VIEWER_CELL_SIZE;
-    const shapeWidth = item.shape?.width ?? 1;
-    const shapeHeight = item.shape?.height ?? 1;
-
-    // Calculate target grid position based on container center
-    const targetX = Math.round((container.x - cellSize / 2) / cellSize);
-    const targetY = Math.round((container.y - cellSize / 2) / cellSize);
-
-    // Clamp to inventory bounds
-    const clampedX = Math.max(
-      0,
-      Math.min(targetX, inventory.width - shapeWidth),
-    );
-    const clampedY = Math.max(
-      0,
-      Math.min(targetY, inventory.height - shapeHeight),
-    );
-
-    // If position changed, notify callback
-    if (
-      clampedX !== item.transform.offset.x ||
-      clampedY !== item.transform.offset.y
-    ) {
-      this.callbacks.onMoveItem(itemId, clampedX, clampedY);
-    } else {
-      // Snap back to original position
-      const originalX = this.gridOffsetX + item.transform.offset.x * cellSize;
-      const originalY = this.gridOffsetY + item.transform.offset.y * cellSize;
-
-      this.scene.tweens.add({
-        targets: container,
-        x: originalX,
-        y: originalY,
-        duration: 150,
-        ease: "Power2",
-      });
-    }
-  }
-
-  onUpdate(
-    entry: [string, InventoryItem<GameItemMeta>],
-    obj: Phaser.GameObjects.Container,
-  ): void {
-    const [, item] = entry;
-    const cells = this.getCells(item);
-
-    if (cells.length > 0) {
-      // Don't animate if currently dragging this item
-      if (this.dragState?.itemId !== entry[0]) {
-        const worldX =
-          this.gridOffsetX + cells[0].x * GRID_CONFIG.VIEWER_CELL_SIZE;
-        const worldY =
-          this.gridOffsetY + cells[0].y * GRID_CONFIG.VIEWER_CELL_SIZE;
-
-        this.scene.tweens.add({
-          targets: obj,
-          x: worldX,
-          y: worldY,
-          duration: 200,
-          ease: "Power2",
-        });
-      }
-    }
-  }
-
-  onDespawn(obj: Phaser.GameObjects.Container): void {
-    this.scene.tweens.add({
-      targets: obj,
-      alpha: 0,
-      scale: 0.5,
-      duration: 200,
-      ease: "Back.easeIn",
-      onComplete: () => obj.destroy(),
-    });
-  }
-}
-
-export function createInventoryItemSpawner(
-  scene: Phaser.Scene,
-  inventorySignal: InventorySignal,
-  gridOffsetX: number,
-  gridOffsetY: number,
-  callbacks: InventoryItemSpawnerCallbacks,
-) {
-  return spawnEffect(
-    new InventoryItemSpawner(
-      scene,
-      inventorySignal,
-      gridOffsetX,
-      gridOffsetY,
-      callbacks,
-    ),
-  );
-}
diff --git a/packages/sts-like-viewer/src/scenes/InventoryTestScene.ts b/packages/sts-like-viewer/src/scenes/InventoryTestScene.ts
index 408d045..53a88e2 100644
--- a/packages/sts-like-viewer/src/scenes/InventoryTestScene.ts
+++ b/packages/sts-like-viewer/src/scenes/InventoryTestScene.ts
@@ -3,7 +3,7 @@ import { createButton } from "@/utils/createButton";
 import { GRID_CONFIG } from "@/config";
 import { createInventorySignal, moveItem } from "@/state/inventory";
 import { createItemIn, data } from "boardgame-core/samples/slay-the-spire-like";
-import { createInventoryItemSpawner } from "./InventoryItemSpawner";
+import { createInventoryItemSpawner } from "@/gameobjects/InventoryItemSpawner";
 import { SceneKey } from "./types";
 
 export class InventoryTestScene extends ReactiveScene {
@@ -54,34 +54,36 @@ export class InventoryTestScene extends ReactiveScene {
   private drawGrid(invWidth: number, invHeight: number): void {
     const graphics = this.add.graphics();
 
-    for (let y = 0; y < invHeight; y++) {
-      for (let x = 0; x < invWidth; x++) {
-        const px = this.gridOffsetX + x * GRID_CONFIG.VIEWER_CELL_SIZE;
-        const py = this.gridOffsetY + y * GRID_CONFIG.VIEWER_CELL_SIZE;
+    this.addEffect(() => {
+      for (let y = 0; y < invHeight; y++) {
+        for (let x = 0; x < invWidth; x++) {
+          const px = this.gridOffsetX + x * GRID_CONFIG.VIEWER_CELL_SIZE;
+          const py = this.gridOffsetY + y * GRID_CONFIG.VIEWER_CELL_SIZE;
 
-        const isOccupied = this.inventorySignal.value.occupiedCells.has(
-          `${x},${y}`,
-        );
-        graphics.fillStyle(
-          isOccupied
-            ? GRID_CONFIG.CELL_OCCUPIED_COLOR
-            : GRID_CONFIG.CELL_EMPTY_COLOR,
-        );
-        graphics.fillRect(
-          px + 1,
-          py + 1,
-          GRID_CONFIG.VIEWER_CELL_SIZE - 2,
-          GRID_CONFIG.VIEWER_CELL_SIZE - 2,
-        );
-        graphics.lineStyle(1, GRID_CONFIG.GRID_LINE_COLOR);
-        graphics.strokeRect(
-          px,
-          py,
-          GRID_CONFIG.VIEWER_CELL_SIZE,
-          GRID_CONFIG.VIEWER_CELL_SIZE,
-        );
+          const isOccupied = this.inventorySignal.value.occupiedCells.has(
+            `${x},${y}`,
+          );
+          graphics.fillStyle(
+            isOccupied
+              ? GRID_CONFIG.CELL_OCCUPIED_COLOR
+              : GRID_CONFIG.CELL_EMPTY_COLOR,
+          );
+          graphics.fillRect(
+            px + 1,
+            py + 1,
+            GRID_CONFIG.VIEWER_CELL_SIZE - 2,
+            GRID_CONFIG.VIEWER_CELL_SIZE - 2,
+          );
+          graphics.lineStyle(1, GRID_CONFIG.GRID_LINE_COLOR);
+          graphics.strokeRect(
+            px,
+            py,
+            GRID_CONFIG.VIEWER_CELL_SIZE,
+            GRID_CONFIG.VIEWER_CELL_SIZE,
+          );
+        }
       }
-    }
+    });
   }
 
   private setupItemSpawner(): void {
@@ -92,7 +94,7 @@ export class InventoryTestScene extends ReactiveScene {
       this.gridOffsetY,
       {
         onMoveItem: (itemId: string, newX: number, newY: number) => {
-          moveItem(this.inventorySignal, itemId, newX, newY);
+          return moveItem(this.inventorySignal, itemId, newX, newY);
         },
       },
     );