Pretty much all the glitches I've encountered ingame were induced glitches that I decided to try. I once spent a few hours playing around with the Mew Glitch in Red just to see what sort of crazy shite it could produce. The strangest glitch I recall, though, was one in the Japanese Gen 2 involving the national park and the Red Gyarados, which turned a Pokémon shiny upon evolution. Let's just say the end result was a purple Vaporeon with the Red Gyarados' moveset. Dragon Raging Vaporeon, what will they think of next, Volt Tackling Fearow?