Piestar:
...or even more bizarrely, your class?
I had that happen to my character in a Star Wars game. But it was an alternate timeline version of the game, and EVERYONE's characters got switched up. It was also a face-to-face game that we'd been playing for years (my character had been used for most of a decade, retired, then pulled off the shelf again at the GMs request because of a one-off for a friend coming back into town, and we all realized we missed him (the character) so I kept playing him for a few more years...), so we all knew each other very well and the GM didn't put anyone in a situation that they found uncomfortable or offensive.
Personally, I found it very intriguing, because it gave me a chance to see how similar the character could be to the original while being almost antithetical to the original (the original character was a bounty hunter who was basically a Force-denier and thought everyone claiming to believe in the Force or the Jedi was delusional...the alternate version was a Jedi Master who'd been trained by Anakin Skywalker--who, in the alternate timeline, had never turned to the Dark Side.)
As a further wrinkle, after the time-space...whatever...that bounced us all into that alternate reality, he had each of us roll to see if we remembered our original selves. It became a series of changes...and through them all, mine was the only character who had absolutely no recollection of his original self...)
All that said...I can see where something like that could be upsetting to a player. If it had been a different GM...if we hadn't played for so many years and known each other so well...if someone had been singled out for it while everyone else was left in their original character...I could see people being upset by it, because those weren't the characters they created to play. The GM starts changing defining traits of a character like that, and suddenly it stops being the character you wanted to play, and becomes a character the GM wants you to play, and that's not always the same thing. And if you don't know the GM REALLY well, it's hard to trust that there's going to be a payoff for becoming the guinea pig.