Why are we here?

would stop the joker inflation in the comic book market and force them to use another character

It's just that both writers and readers straight-up forget about all those successful examples and focus so much on the Joker, the one villain who seems to be doing villain things with the very specific purpose of forcing Batman to break his no-kill rule.

They weren’t even the one who got the worst of it. What is wrong with them, that they’d sit there and relive their friend’s worst moments like that?

Jamming a metal tube through them (and pushing the contents that got stuck in the tube out with a smaller metal rod, making it completely see-through)

Shove them in a woodchipper. See what happens

Making a hole in their chest so they can only breathe when you hold it closed. Making them beg for you to hold it closed .

Cutting something off (or out) and making them eat it. Doing this a few times:)

Break them. In the literal sense.

Make a hole in their side and install a transparent window. so you can see inside them whenever. Or a ring with no cover, so you can even reach inside them whenever

Fold them into a suitcase and keep them like that. Push it down a staircase or two.

What if they are killed as punishment for every little thing. What if sometimes they're killed even though they've done a good job, just for the hell of it. What if as a reward for good behaviour Whumper asks them how they'd like it done.

And then maybe they ask for something painless, or quick so they could get this over with. Or maybe they're still defiant and request a death they know would inconvenience Whumper (Whumper hates getting their floor dirty? Get your own brain matter spilled on the floor). Maybe they're curious, maybe they've never seen inside a ribcage before, maybe they ask for a new and interesting way to die each time. Maybe they rise from their own ashes each time like a phoenix, and ask to be burned alive because it's gonna happen anyway.

And then when they're finally out, maybe they fuck up, and immediately hand Caretaker a knife. Maybe Caretaker reacts in shock and horror, and Whumpee helps guide the blade through their neck. Or maybe they cooperate with Caretaker, and then state monotonously that they'd like to just have a lethal injection this time, if it's not too much trouble. Or maybe they leave notes on medical books that seem incredibly personal ("actually, iokane powder does have a taste, it burns in your throat").

Maybe they have favourite and least favourite ways to die, and discuss their opinions at inconvenient times. Maybe they want to be a doctor because "dying sucks", or because they want to put their knowledge to good use.

"Not so easy, bitch! You're gonna take a hit for each of them."

"Suit yourself."

"And also, you're gonna pick where I hit you."

"Very well. My left thigh."

"Oh, I see what you're doing here, strategically minimizing the impact. And that won't do. What kind of a sacrifice even is that? Nnnnah. Choose again. Something painful. Or something vital."

"Shit... You're a sick mofo, you know that? Alright... Alright. Break my nose then?"

"Really? Oh come now, for a nine-year old girl? She's worth more, don't you think?“

"Shhhit..."

"Choose! Or I'll—“

"Kidney! Please don't hurt her! Kick me in the kidney."

Loosening their restraints and holding their hands.

Pulling the gag away from their mouth so they can drag in a proper breath because they're sobbing/hiccuping/hyperventilating.

Brutal hands that inflict so much pain turning soft - a hand carded through their hair, warm palm placed on Whumpee's heaving chest as they're asked to mimic Whumper's breathing. Wiping the tears away.

Offering a sip of water. Offering them praise like; "It's okay, deep breaths," "Not long now, whumpee", "You're being so good for me."

And once Whumpee's finally calm and regulated?