I once saw a better list of Hulk feats online, but this will have to do: http://www.incrediblehulk.com/incrediblefeats.html

Among some of the feats listed there, I'd say destroying an asteroid twice the size of the Earth with one punch ranks up there pretty high on the "holy crap" scale. I love seeing those who know nothing about the character trying to say Sephiroth would win. Hulk would eat him in his base form (literally if we're talking about Ultimate Hulk), let alone as he keeps getting more angry, and by extension, much more powerful. I really don't think there's anything Sephiroth could do to damage him permanently.