This isn't quite whump, but you could add in whump if you wanted to😛
So, villain is a poor guy who reeaally wants to be a really bad guy, but they really suck at it. Any time they try to be bad, they end up failing horribly. If they ever succeed in doing anything evil, it's 100% an accident.
So this villain finally bakes up this actually really good plan, and sets it into motion. Fast forward to the end of it, the heroes have won, and the villain has been captured. The heroes are making fun of the villain for once again failing, but the villain has one last trick up his sleeve.
"Fine, whatever! I may have failed to achieve my ultimate goal, but I still succeeded in one thing!" Villain laughs evilly.
"And what, pray tell, is that?" The leader scoffs.
"I poisoned you! I put snake venom in your drink!" Villain spits with an evil grin. The team chuckles, then sees leader, who's turned white.
"They... they didn't actually... right, Leader?" One member asks in a hushed tone. Leader shakes their head. They'd been feeling sick since yesterday, after they'd gone out for drinks with a friend, and had been wondering why.
"I saw you in the bar last night, I did it then! And you didn't even notice!" Villain smirks. "It's much too late to do anything, though! You'll be dead by tonight!"
The teammates, panicked, look to the medic, who's been sitting in their spot, head bowed, shoulders shaking with their face in their hands. The team is terrified. Is it really so late that even the medic is reduced to tears?
"Hey, M-Medic, it's okay..." Leader says softly, laying a hand on their shoulder, and suddenly realize--medic is laughing.
The whole room is silent as the medic sits there, busting a gut.
"What's so funny?" One teammate asks, trying to hide the tremor in their voice. Has medic gone made? Has he been possessed. "What's so funny?!" They repeat, demanding answers. The medic struggles to catch their breath, trying to explain like they're trying to tell a joke that's just too damn funny.
"Oh, villain, snake venom--hee hee haahahaa--snake venom isn't toxic--hahaaa--when swallowed!" They chortle, tears running down their cheeks. Villain's face falls.
"What? What are you talking about?!" Villain hisses.
"It's a protein! When you eat it, your body breaks it down into totally harmless chemicals! It's not a poison!" Medic laughs. "Oh, Villain, I'm so sorry, you tried so hard... hahaaa!!!"
"Are you serious?" One of the teammates ask, another pulling out their phone to google it.
"Yes! You did use snake venom, right?" Medic asks Villain.
"N-no, I used c-cyanide..." Villain lies, obviously. The whole team breathes a sigh of relief, and Villain, disappointed and discouraged, is sent away to prison once again.