Fossil Pokemon FireRed?
By defeating Super Nerd Miguel at the end of Mt. Moon, you will
be able to choose from two Fossils: the Helix Fossil, and the Dome
Fossil. Later in the game, when you make it to Cinnabar Island
where the seventh gym is located, you will be able to change your
fossil back into a Pokémon at the laboratory. If you picked the
Helix Fossil, your Pokémon will be Omanyte, and if you picked the
Dome fossil, your Pokémon will be Kabuto.