Minecraft wiki entry for Creative, associated text: Most blocks give the player a copy of itself when using pick block. Using it on an item frame gives the player the item held inside, or the item frame itself if no item is held. Using it on a mob gives the player a spawn egg of that mob. Using it on a mob head gives the mob type that it is; using it on custom heads gives only the mob type that was used in the command, but without the custom skin.