The Lost Gem Glitch is a minor glitch in Spyro: Year of the Dragon. Sometimes, in Spooky Swamp, there is a chance that one gem will totally vanish, and Sparx will not be able to track it down after completing Spider Town. If this happens, it will be impossible to get 100%, but one can still access Super Bonus Round with a cheat; however, the Sorceress can't be fought at all. This is an unusual glitch, and there is no possible way to stop it, or knowing when it is going to happen.