I tried to save an Entity as NBTTagCompound and then create a new Entity from that NBTTagCompound when hitting an Entity with my item. This is what i have:
@Override
public boolean onLeftClickEntity(ItemStack stack, EntityPlayer player, Entity entity) {
if (!player.world.isRemote ) {
NBTTagCompound ttt = entity.writeToNBT(new NBTTagCompound());
Entity eee = EntityList.createEntityFromNBT(ttt, player.world);
if (eee != null) {
eee.setPosition(player.posX, player.posX, player.