The third episode of Dexter's Laboratory aired on Cartoon Network on May 12, 1996.
Dexter discovers he has a rival with a bigger laboratory---Mandark. He then teams up with DeeDee to stop him.
Dial M for Monkey: Simian
Monkey faces an evil chimpanzee named Simian, who plans to take revenge on humanity.
Old Man Dexter
After Dexter is banned from watching a movie, he devises a plan to accelerate the aging process, but DeeDee's tampering causes Dexter to turn into a 95-year-old.