The Super Smash Bros. Invitation Letter refers to the wax-sealed envelope sent to characters officially joining the roster of Nintendo’s flagship fighting series. The imagery became legendary through reveal trailers for games like Super Smash Bros. Ultimate, where the sight of the red logo seal signaled a high-stakes arrival. Online, the meme is used to ironically 'invite' unlikely candidates—ranging from Shrek and Goku to real-life figures or abstract concepts—into the fight. It symbolizes a moment of ultimate prestige or a dramatic entry into a new situation, often accompanied by the signature 'JOIN THE BATTLE' tagline.