Bup refers to a sound effect and a visually distorted image of Toad from the Mario franchise, which gained legendary status within the Super Mario 64 ROM hacking and speedrunning communities. The meme was popularized primarily by the Twitch streamer SimpleFlips, stemming from a sound bite where Toad's voice is cut off or compressed into a short, percussive 'bup.' Visually, it is often represented by a low-resolution or 'squished' sprite of Toad staring blankly. Over the years, Bup has evolved into a symbol of chaotic humor and a recurring inside joke for viewers, often used to signify a sudden fail, a weird glitch, or simply as a surreal punchline in various internet edits.