This is quite honestly thing that would make me leave table, if my DM would do that to me ...
They want you to do something, whole campaign everything leads to this singular deed ...
You decide to do it ... but not in the way they wanted you to ...
So they set HUUUUUUUUUUGE DC so it would be impossible to sucess ...
But based on previously established homebrew rules ... you manage to suceed anyway ...
And yet you fail anyway.
FOR SOMEONE'S SAKE WHY EVEN LET US TRY IF THERE IS ONLY ONE OUTCOME!? -_-
That's not quite right though.
You decide to do it in EXACTLY the way they wanted you to, but you/your character didn't know that the attempt was always going to be futile.
How should a tabletop DM handle something that?
As I understand it, landing a crit does do something, but not what you were hoping for.
