You are excrement. You can change yourself into gold.
There are cards that will exhaust enemies (mostly rogue and survivor, but others too). Other than that (and the tongue in cheek answer above), the only way in the rules to explicitly exhaust an enemy is to evade.
Then Golden Pocket Watch to skip the Unkeep phase.
That's a really interesting idea. Very situational -- I imagine you're usually going to be better off repeating the investigation phase -- but if it's late in the game and you still have weaknesses lurking, maybe.