The categorical dual of a monad is a comonad. A comonad is therefore a functor with natural transformations counit and... Wait, never mind. Comonad is a guy. He is
not also The Guy. He started the pages for Starcrash, Scripted Battle, That One Attack, and Analysis.Persona3.
He's currently running a liveforum/liveblog/let's play/whatever of Planescape: Torment. He will finish it eventually.
A member of KNIVES.