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.
This glitch is caused by killing one of the Mosquitoes for the first time over the water, without having Sparx. This causes the gem to fall into the water and become unretrievable.
Similar things can occur in other levels with bottomless pits but the game ensures that you receive gems lost this way. It just glitches out in Spooky Swamp.
|Swim in the air - Skip through the game - Double Jump - Dead Mode|
Proxy Run - Proxy Jump - Collision Free - Unlimited Fall - Lost Gem - Fluffy
|Air Rolling - Dark Spyro - Unlimited Fall|
|Unlimited Flight Glitch|