Half-Shell Heroes: Blast to the Past is a television special from the Teenage Mutant Ninja Turtles franchise loosely connected to the 2012 TV cartoon. The special draws inspiration from the Half-Shell Heroes toyline, which depicts the Turtles as children who remain fully mutated with their full compartment of ninja skills. It aired on Nickelodeon on November 22, 2015 and was released on DVD on March 15, 2016.
In the special, the turtles recover a crystal Shredder's henchmen stole from a museum. Donnie tries to use it as a power source for his transforming turtle robot, but using the robot's rocket boosters accidentally sends the turtles back to dinosaur times with Bebop and Rocksteady hitching a ride. The turtles must find a way back home, but with the Triceratons causing trouble, that's easier said than done.
- Alternate Continuity: The special has enough inconsistencies in continuity that it is clearly not canon to the main series. Chief among them is that the special premiered at a point in the main series where the Triceratons destroyed the Earth and the Turtles went with Professor Honeycutt in space, time-traveling six months prior to Earth's destruction to try and prevent it by gathering the pieces of the Black Hole Generator before the Triceratons can use it.
- Anachronistic Animal: Not only are Stegosaurus, Brachiosaurus, and Compsognathus shown living in the Cretaceous rather than the Jurassic, but most of the Cretaceous animals in the special didn't actually live 100 million years ago.
- Androcles' Lion: Raph befriends the Pteranodon by treating its injured wing.
- Art Shift: Is done in a much lighter, more cartoon-y style than the main series.
- Comedic Underwear Exposure: The Triceratons at one point end up in their underwear. This includes the female general Zera.
- The Comically Serious: Tiger Claw knows that humans and dinosaurs didn't exist together, unlike Bebop and Rocksteady.
- The Cuckoolander Was Right: When the Turtles and their tamed Stegosaurus, Triceratops, and Pteranodon get cornered into a cave by a Tyrannosaurus, Mikey suggests to Donnie (who hasn't gotten his own prehistoric companion yet) that he tame it with a slice of pizza with pepperoni, maple syrup, and peppermint. Despite Raph naturally calling him an idiot for it, his plan actually works.
- Denser and Wackier/Lighter and Softer: The humor is much more overt, and the special is overall lighthearted.
- Domesticated Dinosaurs: The turtles befriend and tame dinosaurs (and one pterosaur) to fight the Triceratons.
- Enemy Mine: Bebop and Rocksteady offer to work together with the turtles against the Triceratons. Leo tries to invoke a Heel–Face Turn.
- Even the Dog Is Ashamed: Raph's Pteranodon does the same Face Palm as him when Mikey suggests to Donnie in taming the T. rex with a pizza slice.
- Mythology Gag:
- This isn't the first time the turtles have traveled to dinosaur times.
- When they return to the present, Shredder has taken over the world similar to Same As It Never Was.
- While trapped in prehistoric times, Bebop and Rocksteady's outfits are altered to slightly resemble those of their original incarnations (most notably Bebop's turtle shell shoulder pads, and Rocksteady wearing a yellow vest.)
- Out of Focus/What Happened to the Mouse?: Tiger Claw's only scene in this special is during the museum robbery.
- Raptor Attack: The raptors are, as usual, Jurassic Park-styled. Be it they're organic or mechanical.
- Savage Spinosaurs: The Triceratons release a gigantic robo-Spinosaurus on the Turtles.
- Sequel Hook: When the characters return to the present, they overshoot their destination and discover that Shredder has taken over the world.
- Spin-Off Babies: The theme of the toyline, although the Turtles' ages aren't mentioned in the special itself.
- Spinosaurus Versus T. rex: Played With. Donnie's T. rex faces off against the robo-Spinosaurus, along with the rest of the Turtles' dinosaurs.
- Super-Deformed: Everybody except for the dinos is portrayed in a chibi style.
- Taught by Television: Defied. When the turtles get confronted by a T. rex, Leonardo attempts to use Jurassic Park logic on it. Donatello corrects him that real tyrannosaurs have excellent eyesight better than that of eagles or hawks, and sure enough the T. rex has no trouble seeing them.
- Terrifying Tyrannosaur: The Turtles get chased by a Tyrannosaurus that scares off a pack of raptors surrounding them, and then they get menaced by a second, much bigger Tyrannosaurus. The first T. rex, however, ends up being tamed by Donnie who feeds it a pizza slice under Mikey's suggestion.
