Dragon Ball Z: Kid Buu
Kid Buu is the original and purest form of the Majin called Buu
Although he appears smaller than any other form, he is more dangerous than any other forms of Buu, due to his full relentless evil and unpredictability.
He retains his childish personality, becoming amused and laughing hysterically at his own destruction of entire worlds.
(wished I could make him scowl more but no item would allow it lol)