Blue Boomerang, Mime Boomerang or Lapiz Lazuli Boomerang is a Boomerang which is the strongest and Fastest. It is an unlimited in use, melee weapon. Just press button two (right click) and It is off in air. Unlike other Boomerangs, this one cannot damage you, unless you are in a server.
It gives 12 Damage (6 Hearts). It can kill any Passive Mob (except Passive Creepers or Cat Creepers) or Neutral Mob in an OTK. Blue Boomerangs can be enchanted without not being ranged. When Drinking Strength Potion it can kill any Mob (except Bosses which takes half or a third of its life) in an OTK.