Pinwheel
Pinwheel from Dark Souls.
On a game where everything turns you into poo, there comes this weird magic using guy, I rushed to him hitting like crazy and was surprised when he went down in 3 or 4 hits.
Pinwheel's actually one of my favourite bosses in the game.
He has the most unique music and setting but I agree, he's a pushover. Unless you give him too much time. My only thought could be that after a grueling area like The Catacombs, the developers expected you to expect a tough boss fight. Whereas the secret to Pinwheel is to just rush him, they might have felt you would'v been precautious and therefore quickly lost control of the fight.