The "Mew Under the Truck" legend is an urban legend revolving around the 1996 role-playing games Pokémon Red and Blue.
Near the S.S. Anne ship in Vermillion City, there is a secret ledge that is home to a single pick-up truck of unknown origin. The only way to access this ledge is to have a Pokémon use the move “Surf”, which allows you to cross bodies of water, and surf around the ship. Unfortunately, under normal circumstances, the ship, and by extension access to the water, leaves forever before players would obtain “Surf”.
Clever players have found ways to get around this, either by trading in a Pokémon from another game that already possesses “Surf” or by intentionally losing a battle on the ship after obtaining the move, sending them back to town without triggering the departure of the ship. Although, and possibly because, Nintendo has yet to explain the purpose of the truck, players began spreading rumors that either a rare item or the rare Pokémon known as Mew could be found underneath the truck. While this was not true initially, later releases of the games did hide a rare item underneath as a reference to the original rumor.