Tonton Streaming Dexter's Laboratory (1996) S1E7 - Dexter's Rival

Mandark Astronomanov, a new student at Dexter's school, seems to be superior to Dexter academically. Mandark forces Dexter to shut down his lab so that Mandark's lab can gain more power. However, with the help of Dee Dee, Dexter manages to destroy Mandark's lab.