Blinder (for lack of a better name)

A new mob called the Blinder would spawn in the deep dark. It would only spawn near Wardens, and in large caves. These small creatures would scream every once and a while, blinding all entities nearby (The scream also alerts the Warden, but does not get it angry). This mob would also be tamable using Glow Berries. If a tamed Blinder notices its owner being targeted by a Warden, it would run about 10-20 blocks away and scream, blinding the player but also luring away the Warden. This scream, unlike its regular ones, would anger the Warden and cause it to attack the Blinder. It would drop an item that can be used to make Blindness potions, but only when killed by a Warden.