Dexter_s Laboratory ｜ King of Koosland ｜ Cartoon Network

Dee Dee enters the land of her imaginary friend Koosalagoopagoop after he lies to her that he is the king of his land. Past the vaulted doors lives the smartest boy the world has ever seen, Dexter, boy genius! He's constantly creating dazzling, world-saving inventions in his secret laboratory. His big sister Dee Dee frequently wrecks his experiments. However, he has bigger problems such as his nemesis, Mandark, his brilliant rival at Huber Elementary School. Mom and Dad, of course, have no idea what their little angel is up to.