So Sorry is a hidden miniboss encounter in Undertale, and was bought-in as a Kickstarter goal. The encounter can only be triggered on October 10th of any year, and either any time of day on the Switch version, or between 8:00 and 8:59 PM on the Steam version. He appears in Hotland, in a specific room on the second floor. He cannot be encountered in a Genocide Route, as the entire second floor of Hotland is inaccessible during the route.

His real name is never given (much like with Burgerpants) but true to his nickname, he apologizes a lot during his encounter, as his attacks come from clumsiness and enthusiasm for showing off his art, and not deliberate attempts to hurt the protagonist.

He is an orange monster with brown accents on his body, and light brown hair on his head. In battle, he will wear one of five different hats; a party hat, a tiny cowboy hat, a jester hat, a beret, or a fedora.