Leonardo Lightens Up
Teenage Mutant Ninja Turtles (1987 Cartoon) episode
Leonardo Lightens Up Title Card.png
Season Code: 04
Episode: 19
Original airdate September 29, 1990
Written by Dan DiStefano
Supervising Producer Fred Wolf
Producers: Walt Kubiak
Supervising Director  Bill Wolf
Episode chronology
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"Slash - The Evil Turtle from Dimension X" "Were-Rats from Channel 6"
Teenage Mutant Ninja Turtles 1990 Season
September 10, 1990 - December 8, 1990
List of Teenage Mutant Ninja Turtles episodes


  • Syndication
  1. "Plan Six From Outer Space"
  2. "Turtles of the Jungle"
  3. "Michelangelo Toys Around"
  4. "Peking Turtle"
  5. "Shredder's Mom"
  6. "Four Turtles and a Baby"
  7. "Turtlemaniac"
  8. "Rondo in New York"
  9. "Planet of the Turtles"
  10. "Name That Toon"
  11. "Menace Maestro, Please"
  12. "Superhero for a Day"
  13. "Back to the Egg"
  • Saturday Mornings
  1. "Son of Return of the Fly II"
  2. "Raphael Knocks 'em Dead"
  3. "Bebop and Rocksteady Conquer the Universe"
  4. "Raphael Meets His Match"
  5. "Slash - The Evil Turtle from Dimension X"
  6. "Leonardo Lightens Up"
  7. "Were-Rats from Channel 6"
  8. "Funny, They Shrunk Michelangelo"
  9. "The Big Zipp Attack"
  10. "Donatello Makes Time"
  11. "Farewell, Lotus Blossom"
  12. "Rebel Without a Fin"
  13. "Rhino-Man"
  14. "Michelangelo Meets Bugman"
  15. "Poor Little Rich Turtle"
  16. "What's Michelangelo Good For?"
  17. "The Dimension X Story"
  18. "Donatello's Degree"
  19. "The Big Cufflink Caper!"
  20. "Leonardo Versus Tempestra"
  21. "Splinter Vanishes"
  22. "Raphael Drives 'Em Wild"
  23. "Beyond the Donatello Nebula"
  24. "Big Bug Blunder"
  25. "The Foot Soldiers are Revolting"
  26. "Unidentified Flying Leonardo"

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Leonardo Lightens Up is a season 4 episode of the 1987 TV series.


Splinter is away, leaving Leonardo in charge. Unfortunately, he's having trouble keeping his brothers in line with their ninja exercises: Raphael watches TV, Donatello works on his inventions, and Michelangelo makes pizza. All three tell him to "lighten up."

Raphael suggests that they should use the personality modifier ray on Leonardo. Donatello's argued that it isn't perfected yet. As Raphael, Michelangelo, and Donatello begin to roughhouse, they accidentally zap Leonardo with the personality ray and turned him into a a fun loving but an irresponsible character.

Meanwhile, some goons are setting up giant speakers atop a building, on behalf of the villainous Maestro G. Cleff, who uses sound waves to cause chaos. April and Vernon attempt to cover the story, only for their equipment to disintegrate and buildings to start collapsing. While the mayhem is going on, Cleff's goons are robbing the treasury. April manages to escape into the sewer, and heads for the lair.

Leonardo's new lighthearted approach becomes extremely out of control. The way Leonardo is behaving doesn’t seem like himself, like pulling pranks on his brothers. At dinner time he dressed up as a French sever and serves them an exploding turkey and sprays them with water. April arrives and tells them about Cleff, which motivates them to turn him back to normal. Unfortunately, Leonardo has already left to "enjoy himself" at the beach.

Cleff uses his speakers to rob another bank, planning to use the money to build even more powerful speakers.

The Turtles manage to find Leonardo sunning himself, and he dismisses their concerns about the "mad Maestro." They try to tackle Cleff without Leonardo, wearing special protective helmets, but the music is loud enough that the helmets simply explode and the Turtle Blimp plummets to the ground.

They realize they need Leonardo, and track him down where he's skateboarding. They try to capture him, but his ninja skills are undiminished by his new mindset.

Just then, Splinter returns home and hears what they have been doing since he left. His idea is to challenge Leonardo to a skateboarding contest, and if he wins, Leonardo must return to the lair. Splinter manages to subdue him, and Donatello uses the ray to return Leonardo to his usual bossy, mature, responsible self.

The reunited Turtles confronted Cleff, and don earmuffs to block out his devastating music. Leonardo easily destroys his keyboard and Michelangelo wrecks the giant speakers.

Cleff and his henchmen are arrested, and Splinter reminds the Turtles that all kinds of people are needed in the world, including ones like Leonardo.





  • Turtlecom
  • Personality alterator
  • G.Clef's Super Stereo
  • Soundproof helmets

Home media releases


  • Teenage Mutant Ninja Turtles: Leonardo Lightens Up




  • When Raphael takes the television remote from Leonardo, the close-up shot shows Leonardo's hand changing the channel, when Raphael has the remote.
  • When Donatello told Leonardo he had to get back to his workshop, the background showed a plastered and painted wall instead of the normal sewer brick wall.
  • The Turtles tried to get Leonardo back to the Turtle Lair to reverse the effects of the Personality Modifier. Why didn't they just take the Personality Modifier with them and use it on Leonardo at the skateboarding area he's at?


  • First appearance of Donatello's Personality Alterator device.
  • Raphael quotes The Shining when he says "all work and no play makes Raphael a dull turtle".
  • Raphael breaks the fourth wall when he says "don't you just hate a back seat blimp driver".


  • Man: Hey that's gotta be the loudest sound I ever heard!!
  • Woman: What? I can't hear you! Someone's making the loudest sound I ever heard!!
  • Man: I'm getting outta here!!
  • Woman: Not me! I'm getting outta here!!
  • Michelangelo: Whoa, I am one hungry turtle!
  • Raphael: Yeah. *whistle* Hey, Leonardo, where's our dinner?
  • Leonardo: *in a French accent* Voila! Ho ho ho, le diner, is, how do you say, she's a served!
  • Donatello: Great, roast turkey! *The turkey explodes*
  • Leonardo: *laughs* Oh, you guys oughta see yourselves! What a bunch of... of turkey-covered... turkeys! *Still laughing*
  • Donatello: You're a real barrel of monkeys, you know that Leonardo?
  • Michelangelo: Yeah, dude! That exploding turkey was a total YUCK!
  • Raphael: "Yuck" is the perfect word.
  • Donatello: Who's gonna clean up this mess?
  • Leonardo:*French accent* Never fear, monsieur! I will take care of it to a suite! *pulls out a water tank and sprays the turtles* How do you say in my country: Au reservoir! *laughs* Get it? *Laughs a little more, then runs away*


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