My god, Mundo is awesome.
First time PvP Mundo, my team had a Yi disconnect, and a suicidal Fiddlesticks. The other two players were decent. Anyway, during the game, I saw Twitch escaping through the jungle, predicted his movements, and about 5 seconds after he disappeared, I cleaver-ed him while he was invisible for the kill.
We still lost though. Boo hoo.