Arrow spell cobweb destroys half blocks so also beds.
When shooting a bow on a half block it dissapears and a cobweb spawns. It should spawn on the block above as long as its air. Also the blocks that are placed by the bow are unbreakable so other players cannot remove them. It says the message that you get when you try to destroy a normal world block. http://prntscr.com/pw4n1k