Yamcha's Ultimate challenge
Yamcha vs Superman, Arceus, Screampaste, Goku, Thor, Bills, Spawn, Naruto, Ichigo, Luffy, Galactus, Iceman, Deathstroke, Dr. Fate and the entire MK and SF verse and Docter Doom. This is how I would see it happen.
they all try to blitz him then Yamcha uses his awesome fail power to slip on a banana and fail at life they makes everybody laugh themselves to death so in my opinion Yamcha solos with his awesome fail power.