Entity NBT Data help

Hello, I need some help with my entity throwable and entity living.  I know very little about NBT data and how it works and was wondering if someone could help me. What I plan to happen is for a player to throw an entity throwable at an item. That projectile will "collect" the item and will die when it hit the item. Then a entity living will spawn. When you kill this entity living it will drop the item the projectile hit. So Far I have the projectile hitting the item mechanics worked out but am unable to figure out how to transfer the projectile's NBT to the entity living.

protected void onImpact(MovingObjectPosition par1MovingObjectPosition)
    {

     
    
      
         if (par1MovingObjectPosition.entityHit == null){
        List itemList = this.worldObj.getEntitiesWithinAABB(EntityItem.class,  AxisAlignedBB.getBoundingBox(this.posX - 1, this.posY -1, this.posZ -1, this.posX + 1, this.posY + 1, this.posZ + 1));
         if(!itemList.isEmpty()){
    
      
                          System.out.println("ITEM HIT");
                     EntityItem entity = (EntityItem)itemList.get(0); //this is the item thats in it
                     ItemStack itemStack = entity.getEntityItem();
      
      mcreator_sBubble.EntitysBubble result = new mcreator_sBubble.EntitysBubble(this.worldObj);  //the bubble item
      result.setTagCompound(new NBTTagCompound()); // sets NBT for bubble
                         //sets the bubbles answer to empy
      Item item = itemStack.getItem(); //item's id
      int id = Item.getIdFromItem(item); //getting the id
      
      NBTTagCompound compound = new NBTTagCompound();
                               entity.writeToNBT(compound); //item written to NBT
      
      
      stack.getTagCompound().setTag("ItemData" , compound);
      
      
                    
     if (!this.worldObj.isRemote)
        {
         
          
           entity.setDead();
            this.setDead();
        }
 
 
         
    }
    }
 

Thats what I have so far.  As of the entity living I have the basis of it but no actual code for the NBT transfer. Any help would be appreciated.