Teresa is the Japanese name for Boo, the recurring ghost character from the Super Mario series, including Super Mario Bros. Rather than a human-style full name, the character is typically known by a single name. Teresa appears as a mischievous, floating ghost that often chases Mario and friends, hides when stared at, and becomes active when the player looks away. The character serves as a common enemy, obstacle, and sometimes a friendly or playable figure in later Mario titles, adding a spooky but playful element to the series.