DM: Before you do take that mulligan, could I have you roll Perception?
Twilight Sparkle: Uh... <roll> 19?
DM: Carry on.
Twilight Sparkle: Ooooooo...kay... Listen, Shining. I was just wondering... Have you noticed anything different about–?
Princess Cadance: *A-HEM.*
Twilight Sparkle: Are... you... *KIDDING* me?!
DM: Nope. You turn around and see Cadance at the top of the second-story landing. Almost as if out of nowhere. You could have sworn that the rest of the house was completely empty.
Shining Armor: Oh, hi honey! Didn't realize you were back already.
Twilight Sparkle: I really didn't sense anything?
DM: No hoofsteps, no creaking floorboards, no telltale signs of teleporation, nothing.
Twilight Sparkle: So it's doubly confirmed that she's very stealthy, then.
DM: Doubly inferable, but yes.
It's my birthday once again, it seems. And on par for this hell-year, everything's very weird and tense.
I'll have a State of the Spud post probably up by this point (and as a warning, it's probably going to be really, really sad, even for me), but either way: Thanks for still reading and/or supporting this weird little webcomic. As always, it's keeping me going.
Two possible reasons come to mind:
1) Your DM doesn't want to explicitly confirm that what you're attempting is impossible.
2) You're not actually rolling to find out if you succeed; you're rolling to find out whether or not you fail catastrophically.
Or
3) Some of your party members can make it, you just also tried to do the thing.
4) The DM does not have your character sheet memorized and may not even have your sheet, so did not know it was impossible for you.
5) The DM wants you to be flustered.
The GM/DM wants to give you the illusion of being useful or effective, so gives you a roll that ultimately means nothing so that you won't feel railroaded. But then the Nat 20 comes up and like Hell is he gonna change anything for you so it does nothing.
There was this one time I remember in a really odd Pathfinder campaign where a Nat 20 wasn't enough. Long story short, there was a big bad evil dude with a custom Artifact Sword we caught up with, and through relatively diplomatic shenanigans (read: not immediately trying to murder him or his tribe), I got a chance to look at the sword as a 13th level wizard with Detect Magic and max Spellcraft. Was only able to get some very sparse and not overly helpful info, not all on the Artifact in spite of stats (and I doubt identify would've helped since after dying and getting a forced revive, me and the other player went to a plane to talk with a god about the thing's capabilities - only reason I can think of for not giving the info right there was to force another plot on us we basically were forced to play into and make us interact with gods. Definitely not the best of times...).
I was running a Pathfinder game (The Carrion Crown AP), and part of the adventure involved luring out a serial killer who was targeting vampires (It's kinda a long story).
The players succeeded in luring him out, but he came with friends who tangled most of the party up in melee while *he* tried to run away. The party's monk chased after him and attempted to grapple to stop him from escaping, but unfortunately even with a natural 20 he couldn't score high enough to actually grab the guy.
Fortunately, I'm the sort of DM that rules a Nat 20 gets you something even if it isn't everything you wanted. The monk manages to grab the killer by his hair... only for the hair to slip off like a wig before it changes into a Hat of Disguise. Stripped of his magical disguise, the killer is revealed to be an NPC that was supposedly allied with the vampires, right before said NPC turns into mist and escapes. While he got away, the team at least confirmed who the killer was and were given permission to track him down on behalf of the vampires of the city.
Think of it this way-- potatoes have some of the greatest potential; french fries, au gratin, breakfast hash, tater tots, chips/crisps, and as a battery!
Speaking of characters you wouldn't normally think of having put points into stealth, I like making sneaky healer types. Why don't more people think to make more sneaky healer types? It makes so much sense, Shoot the Medic First and all that, but you can't shoot the medic if you can't see the medic, so combine the sneaky with the healer to make a sneaky healer so they can't Shoot the Medic First.
I'll have a State of the Spud post probably up by this point (and as a warning, it's probably going to be really, really sad, even for me), but either way: Thanks for still reading and/or supporting this weird little webcomic. As always, it's keeping me going.