Blue's Raticate is a theory made by fans of the famous series, Pokémon. In Pokémon Pokemon Red & Blue, during one of the Rival battles, you are exploring the creepy city of Lavendar Town. You enter the Pokémon Tower, fight trainers, blah blah blah. Soon, you meet your rival. Now take note, the last battle against your rival on the S.S. Anne, the teams are....different.
So do you see what is missing? If you guessed Raticate, then you win the grand prize. The Pokémon Tower is where trainers go to mourn over their Pokémon's deaths. Before the battle at the tower, you've probably beaten Blue about 4-5 times? So the theory is, after the battle on S.S. Anne, the attack that fainted the poor Raticate didn't do just that. You killed the poor thing!!