If you guys know about the level 100 gengar or nidoking before brock glitch, I was wondering if it works for any level 1 Pokemon.
In Generation I and Generation II, level 1 Pokémon in the Medium Slow group were calculated to have -54 experience points. However, due to the use of unsigned integers, the game interpreted this value as 16,777,162 experience points. If a level 1 Pokémon with negative experience points completed a battle without gaining enough experience points to reach 0 or higher, the game, attempting to determine its level based on the number of experience points it had, would consider it to be at level 245, but it underflows to level 100.
It is due in-part to this bug that no level 1 Pokémon could be found in the wild without abusing a glitch or hacking the game in Generation I and Generation II. It is also partially for this reason that Pokémon hatched from Eggs at level 5 when Eggs were introduced in Generation II (although level 2-4 Pokémon could be found in the wild).
source So this glitch works only on medium slow Pokemon.