UngeheuerLich
Legend
He did not have pre-established numbers. He didn't have AC, attack bonus, damage, HP, special abilities, or anything. He made them up on the fly. I still consider it fudging, as he was determining our roll results based on whim in the moment "Oh he rolled an 18...yeah I guess that should hit". It makes no difference if there was no pre-existing AC determined vs. he changed it at the last second. In the end, our rolls only mattered if he decided they did.
I do like how your mind jumped to power gaming because I said my enjoyment of the game was removed after my rolls didn't matter. I made a halfling barbarian that threw hand axes. I definitely wasn't power gaming when I made him. I wanted something fun and original. If it matters, this was in 3.5 edition.
There is no way that my decisions and rolls matter more than usual, when they didn't matter until the DM decided they did. We sat down to play D&D, we created characters, made choices of what to specialize in, etc, etc, all because we were playing D&D. We weren't playing a freeform RPG, or a more story centered game. If we were, then I would have less reason to complain when the DM makes story based decisions like that.
Sorry, didn´t want to imply that you are powergaming. Still the DM obviously knew what he was doing. Telling a story. And he must have been really good at math so that you didn´t even notice, something was "wrong".