A stronger mutated form of a bat. Looks a lot like a wyvern and behaves pretty much like one (even makes the same noises). They have powerful attacks so low levelplayers are advised avoid them. After Summer Update 2009 they have slightly weaker poison shot, poison at melee and can no longer drunk.
Knights: try to stay diagonal to avoid poison wave, better hit them in full attack since most damage you will take will come from poison, make sure to trigger chase enemy as soon as it starts running away so you kill them faster, also have exana pox ready to cast as soon as you kill to avoid heavy damage from poison.