diff --git a/src/engine/adapter.js b/src/engine/adapter.js
index 7226c9b25..9d17f92b8 100644
--- a/src/engine/adapter.js
+++ b/src/engine/adapter.js
@@ -1,5 +1,6 @@
 const mutationAdapter = require('./mutation-adapter');
 const html = require('htmlparser2');
+const uid = require('../util/uid');
 
 /**
  * Convert and an individual block DOM to the representation tree.
@@ -11,6 +12,10 @@ const html = require('htmlparser2');
  * @return {undefined}
  */
 const domToBlock = function (blockDOM, blocks, isTopBlock, parent) {
+    if (!blockDOM.attribs.id) {
+        blockDOM.attribs.id = uid();
+    }
+
     // Block skeleton.
     const block = {
         id: blockDOM.attribs.id, // Block ID
@@ -152,7 +157,7 @@ const domToBlocks = function (blocksDOM) {
 /**
  * Adapter between block creation events and block representation which can be
  * used by the Scratch runtime.
- * @param {object} e `Blockly.events.create`
+ * @param {object} e `Blockly.events.create` or `Blockly.events.endDrag`
  * @return {Array.<object>} List of blocks from this CREATE event.
  */
 const adapter = function (e) {
diff --git a/src/engine/blocks.js b/src/engine/blocks.js
index 1b0070bf5..1e22bf73e 100644
--- a/src/engine/blocks.js
+++ b/src/engine/blocks.js
@@ -288,6 +288,22 @@ class Blocks {
                 newCoordinate: e.newCoordinate
             });
             break;
+        case 'dragOutside':
+            if (optRuntime) {
+                optRuntime.emitBlockDragUpdate(e.isOutside);
+            }
+            break;
+        case 'endDrag':
+            if (optRuntime) {
+                optRuntime.emitBlockDragUpdate(false /* areBlocksOverGui */);
+
+                // Drag blocks onto another sprite
+                if (e.isOutside) {
+                    const newBlocks = adapter(e);
+                    optRuntime.emitBlockEndDrag(newBlocks);
+                }
+            }
+            break;
         case 'delete':
             // Don't accept delete events for missing blocks,
             // or shadow blocks being obscured.
diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index aded2ccfb..4da25f7bd 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -379,6 +379,22 @@ class Runtime extends EventEmitter {
         return 'MONITORS_UPDATE';
     }
 
+    /**
+     * Event name for block drag update.
+     * @const {string}
+     */
+    static get BLOCK_DRAG_UPDATE () {
+        return 'BLOCK_DRAG_UPDATE';
+    }
+
+    /**
+     * Event name for block drag end.
+     * @const {string}
+     */
+    static get BLOCK_DRAG_END () {
+        return 'BLOCK_DRAG_END';
+    }
+
     /**
      * Event name for reporting that an extension was added.
      * @const {string}
@@ -1387,6 +1403,22 @@ class Runtime extends EventEmitter {
         }
     }
 
+    /**
+     * Emit whether blocks are being dragged over gui
+     * @param {boolean} areBlocksOverGui True if blocks are dragged out of blocks workspace, false otherwise
+     */
+    emitBlockDragUpdate (areBlocksOverGui) {
+        this.emit(Runtime.BLOCK_DRAG_UPDATE, areBlocksOverGui);
+    }
+
+    /**
+     * Emit event to indicate that the block drag has ended with the blocks outside the blocks workspace
+     * @param {Array.<object>} blocks The set of blocks dragged to the GUI
+     */
+    emitBlockEndDrag (blocks) {
+        this.emit(Runtime.BLOCK_DRAG_END, blocks);
+    }
+
     /**
      * Emit value for reporter to show in the blocks.
      * @param {string} blockId ID for the block.
diff --git a/src/virtual-machine.js b/src/virtual-machine.js
index f9fa45be3..3d3c16791 100644
--- a/src/virtual-machine.js
+++ b/src/virtual-machine.js
@@ -74,6 +74,12 @@ class VirtualMachine extends EventEmitter {
         this.runtime.on(Runtime.MONITORS_UPDATE, monitorList => {
             this.emit(Runtime.MONITORS_UPDATE, monitorList);
         });
+        this.runtime.on(Runtime.BLOCK_DRAG_UPDATE, areBlocksOverGui => {
+            this.emit(Runtime.BLOCK_DRAG_UPDATE, areBlocksOverGui);
+        });
+        this.runtime.on(Runtime.BLOCK_DRAG_END, blocks => {
+            this.emit(Runtime.BLOCK_DRAG_END, blocks);
+        });
         this.runtime.on(Runtime.EXTENSION_ADDED, blocksInfo => {
             this.emit(Runtime.EXTENSION_ADDED, blocksInfo);
         });
@@ -704,6 +710,19 @@ class VirtualMachine extends EventEmitter {
         }
     }
 
+    /**
+     * Called when blocks are dragged from one sprite to another. Adds the blocks to the
+     * workspace of the given target.
+     * @param {!Array<object>} blocks Blocks to add.
+     * @param {!string} targetId Id of target to add blocks to.
+     */
+    shareBlocksToTarget (blocks, targetId) {
+        const target = this.runtime.getTargetById(targetId);
+        for (let i = 0; i < blocks.length; i++) {
+            target.blocks.createBlock(blocks[i]);
+        }
+    }
+
     /**
      * Repopulate the workspace with the blocks of the current editingTarget. This
      * allows us to get around bugs like gui#413.