Years ago, I ended up dropping my Crystal cartridge on some pavement. I had about 200 pokemon in the game overall, and I had over a hundred hours of playtime, so I was praying that nothing had happened to it. When the gameboy came on, the intro was a little glitchy, but I was able to load up my save just fine. My party was alright, but when I checked my PC boxes, all my pokemon had been....spliced or something. I had a caterpie with whirlwind, a magikarp with crazy moves like flamethrower, and so many other pokemon with unlearnable moves. Other than that, my game worked fine.
The good thing about all of it was that I could use those glitch Pokemon in Pokemon Stadium 2! Seeing my Golem use fly was something else.