From Glitch City Laboratories
Not to be confused with the S.S. Anne Ship Truck.
Truck glitch is a minor glitch in Pokémon Ruby and Sapphire Versions, but not in Emerald. It makes the "Littleroot Town" title appear when saving and reseting the game inside the truck, making it get quickly cut due to the other events after the player leaves the truck.
Once you save and reload your game inside the truck, the game does not load the script that prevents the new area's name to be shown, making the game act as like you left, for example, a normal house from Littleroot Town, where the title is normally shown.