The witch hat is a helmet item that gives +3 armor and has 200 durability. It’s traded by the wandering witch and dropped by witches about 7.5% of the time. (100% when the witch is killed by a charged creeper.) It accepts helmet enchantments.
It increases drop chances and amounts of potion ingredients for the following mobs:
Rabbit: Drops rabbit’s foot 100% of the time
Glow Lichen Zombie: drops sightless eye 100% of the time
Ghast: Drops 2 more ghast tears & 2 more gunpowder
Phantom: Drops 2 more phantom membrane
Magma Cube: Drops 2 more magma cream
Breeze: Drops 2 more breeze rods
Spiders: Drop 2 more spider eyes
Witch: Drops 2 more of their random potion ingredient drop
Creeper: Drops 2 more gunpowder
Geomancer: drops 2 more amethyst dust
Quite a fashion statement! It can also be dyed if you want to make sure it matches your outfit.