Colossus

Tactics
The Colossus is a couch potato and moves incredibly slowly. Kiting with Acrid or the Huntress will kill him easily, but any class will wreck him because he only has a short range melee attack. Just go onto a level higher than him and fire away until you achieve sweet victory.

His Clap attack may be able to hit elevated platforms in front of him, and sometimes lag will cause his stomp to have much more range than expected.Colossus