So, by some freakish accident Joker was transported from DC into Doom's laboratory. Doom was recently thwarted by THAT ACCURSED RICHARDS and not in the great mood. So, he is all "so you are a clown? Say something funny, then!"
Rules.
1. Doom is in the very, very bad mood.
2. He will kill Joker if Joker fails to get a smile from him.
3. Joker has 24 hours to do that.
4. He may use resources of Doom's castle (of course he is forbidden to use them against Doom), including teleport. He may go from castle with no more items/etc from Doom's labs (he is permitted to create chemicals there) then he can conceal in his usual outfit.
5. If Joker fails to show Doom something he woud smile at in 24 hours, Doom kills him.
Joker gets access to Doom's tech and 24 hours of prep. Its the Joker, he'll think of a billion ways to do some kind of damage. Create a chemical that will activate the next time Doom flushes his toilet and that will spread all over the country destroying Latveria. You really think Joker will try to actually fight Doom in order to ruin his life? He'll find away to make him smile so Doom would let him go but there's no way Joker would go without leaving some kind of "surprise" behind.
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Azula: My mommy didn't love me so I'm going to burn down your village.