Outburst has never been seen being used in action, but its functions have been described by Izuku. According to him, this Quirk allows Ms. Joke to force others around her to burst into laughter so intense that it dulls their motor skills and cognitive abilities. It is useful for incapacitating villains. The full extent of this Quirks power, as well as its limitations, are currently unknown.
When activated, a blue aura appears around Ms. Joke. It is unclear whether or not Ms. Joke must say anything to make people laugh, or if the laughter is purely spontaneous.