"WHY DID I DO IT... WHY DID I DO IT... WHY DID I DO IT..."
(A messed-up little concept I made for a Bill Cipher given the Giygas treatment - or 'GiyBill' as I call him. My idea was that, after enough time in the Theraprism, he's forced to confront his suppressed memories of what he did to his home dimension, and the guilt that came with it. Unable to reconcile that guilt with what he is now, he loses what little sanity he had left and tears himself apart, becoming a barely-sentient maelstrom of destruction driven by confusion and hatred. It's a small mercy he's contained in the Nightmare Realm again, and lacks any means of escape until it's finally destroyed. Unless some idiot were to try summoning him again...)
(This is my first time drawing something like this so be nice :V)