Yeah, you might need a hard success for this, probably too difficult for your party... > nat 20. Fuck.

Play Pathfinder instead. Nat 20 means nothing.

I do, but I don't run pathfinder as we have another DM that does it. Honestly I love combat in this game. I was mostly referring to any game where you set them to impossible odds (e.g. Cthulhu) and they just roll their highest critical. So basically I either rob them or let them do some John Woo cinematic shit with doves and all.

You can never have enough doves

I once told a player a roll was impossible, so she shouldn't bother. She gave me a look, picked up the dice, and rolled a crit (this was a 3d6 system, so that's a 1 in 216 chance). I don't care what the rules say. If I refused that dice witch her roll, my dice would forever roll naught but garbage.

There's no critical success for ability tests in DnD either.

Yeah, I know. Most DMs know. Most players know. That doesn't mean most actually play that way.

"There’s this emperor, and he asks the shepherd’s boy how many seconds in eternity. And the shepherd’s boy says, ‘There’s this mountain of pure diamond. It takes an hour to climb it and an hour to go around it, and every hundred years a little bird comes and sharpens its beak on the diamond mountain. And when the entire mountain is chiseled away, the first second of eternity will have passed.’ You may think that’s a hell of a long time. Personally, I think that’s a hell of a bird."

I mean, d'you know what eternity is? There's this big mountain, see, a mile high, at the end of the universe, and once every thousand years there's this little bird-"\ -"What little bird?" said Aziraphale suspiciously.\ -"This little bird I'm talking about. And every thousand years-"\ -"The same bird every thousand years?"\ -Crowley hesitated. "Yeah," he said.\ -"Bloody ancient bird, then."\ -"Okay. And every thousand years this bird flies-"\ -"-limps-"\ -"-flies all the way to this mountain and sharpens its beak-"\ -"Hold on. You can't do that. Between here and the end of the universe there's loads of-" The angel waved a hand expansively, if a little unsteadily. "Loads of buggerall, dear boy."\ -"But it gets there anyway," Crowley persevered.\ -"How?"\ -"It doesn't matter!"\ -"It could use a space ship," said the angel.\ Crowley subsided a bit. "Yeah," he said. "If you like. Anyway, this bird-"\ -"Only it is the end of the universe we're talking about," said Aziraphale. "So it'd have to be one of those space ships where your descendants are the ones who get out at the other end. You have to tell your descendants, you say, When you get to the Mountain, you've got to-" He hesitated. "What have\ they got to do?"\ -"Sharpen its beak on the mountain," said Crowley. "And then it flies back-"\ -"-in the space ship-"\ -"And after a thousand years it goes and does it all again," said Crowley quickly.\ \ There was a moment of drunken silence.\ \ -"Seems a lot of effort just to sharpen a beak," mused Aziraphale.\ -"Listen," said Crowley urgently, "the point is that when the bird has worn the mountain down to nothing, right, then-"\ \ Aziraphale opened his mouth. Crowley just knew he was going to make some point about the relative hardness of birds' beaks and granite mountains, and plunged on quickly.\ \ -"-then you still won't have finished watching The Sound of Music."\ \ Aziraphale froze.\ \ -"And you'll enjoy it," Crowley said relentlessly. "You really will."\ -"My dear boy-"\ -"You won't have a choice."\ -"Listen-"\ -"Heaven has no taste."\ -"Now-"\ -"And not one single sushi restaurant."\ \ A look of pain crossed the angel's suddenly very serious face.