Minecraft wiki entry for Development_versions, associated text: A hostile mob.
Its nose slowly bobs up and down when not hostile.
Throws splash potions of poison, slowness, weakness, and instant damage at the player.
Regenerates health over time.
Hold an glass bottle and raise their noses when attacking.
Drink potions of instant health and fire resistance to defend themselves in combat.
Rarely drop potions of instant health and fire resistance.
Is 85% resistant to damage from magic, including poison, instant damage, and thorns, but not strength, sharpness or power.
Does not spawn naturally (yet), but a spawn egg exists for it in Creative mode.