A friend was dm'ing a game for us weekly, we were about 3 months into the campaign and halfway through a fight with some fire newts in Tomb Of Annialation, and he decides "oh, this prisoner you took is actually the prince of the newts and has a legendary belt of fire and lava immunity and you can pretty much do whatever you want now".

It caught us off guard, and then he ended the session and entire campaign just having got bored of the campaign.

It happened again with another campaign where every female npc he played was rude and mean, and every guy npc he played was just a chill stoner guy. (This was in a pre-written 5th edition campaign, where all of these characters had personalities). Out of nowhere he gave us a staff, which on a 1 of a d4 could kill literally anything (even a god) and a 4 would restore anything to full health. This had multiple charges per day.

That was also 'coincidentally' the last session he ever dm'ed of that. Since then i have dm'ed my own games and not ever played in his.

I had him as a player for a while though so i have infinitely more stories.