Reducing ATK to 0

Beelzeus (from Yugioh) has two very unorthodox abilities.

Like most of my other examples; he's impossible to destroy.

His key to this duel however is that he can basically remove the offensive power of his opponent; making them wide open for him to obliterate them. This is quite an odd ability; but a broken one indeed.

Maybe if Saitama does enough pushups he can regain his powers, but he doesn't really have the time to do that in a duel.