As a young box turtle, Spike was flushed down the toilet of his original owner's home, and into the sewers. Raphael then saved him from drowning and took him in as his pet turtle, who Raph has a soft spot for, and often talks to Spike about his feelings in private.
The private feelings conversation between Raph and Spike is important for Raph because he needs Spike as a sounding board for his inner thoughts and feelings. He can't reveal his feelings to his brothers so he shares them with Spike, who can't speak, but is an excellent listener. His brothers tease him about this sometimes, mostly Mikey. Spike's favorite food is lettuce leaves, which he is often seen eating. Raph often lets Spike ride around on his shoulder and his best friend.
Slash and Destroy: When Spike was mutated into Slash, he has a vendetta against the Turtles, because of the stories Raph has told him all these years. Thinking that his brothers mistreated him, Slash set his thoughts on wiping them out anyway he could. He copied Raph's moves and used them to fight. He was last seen being knocked off a large building by losing his footing, after Raph struck him in one of his pressure points.
Metalhead Rewired: Slash returns as a prisoner of the Kraang, and he's not happy one bit. As soon as he's released he starts smashing up robots left and right first by throwing one at another standing by a cell, and even saves Raph as he is about to be hit by a Kraang, before disappearing once again.
Newtralized!: Slash is soon captured by the Kraang a second time and freed by the Newtralizer, who he becomes friends with. Together, the two make a vow to wipe out the Kraang. Slash is pleased with thier progress, but after he sees that the Newtralizer's plans have gone to far, to even wiping out the turtles and the city, he makes peace with Raphael and his brothers and helps them in the fight. Afterwards though, even though he's back on good terms with them, Slash decides that its better if he goes solo, and disappears again.
Battle for New York: Sometime during the Kraang's invasion, Slash is recruited by Jack Kurtzman along with Leatherhead, Pigeon Pete, and Dr. Tyler Rockwell to fight back the Kraang, with Slash leading the team. Together, the four mutants form the Mighty Mutanimals to repel the takeover on New York City. They debut at the beginning of the episode, rescuing the Ninja Turtles from a Kraang attack. Compared to his brothers, Leo still doesn't trust Slash because of his cruel actions of the past.
Clash of the Mutanimals: During a black market which involves Tiger Claw, Slash interrupts the trade and introduced the Mutanimals. They battle, but eventually Tiger Claw wins and takes Slash and Rockwell, leaving Leatherhead and Pete behind. The two retreat to the Turtles so that Leatherhead can tell them that Tiger Claw took Slash and Rockwell, and decide to break them out. At Shredder's lair, Slash is looks at Karai, who is attempting to break herself and them out, and Stockman-Fly arrives and says the Mind Worms are ready for Karai as she angrily hisses at him. Shredder orders him to test it on Slash and Rockwell first, and they escape later and find the Foot after them. The Turtles, Leatherhead and Pete help them, and they return to the lair and give the captured Mutanimals soup when out of nowhere, Slash hits Splinter in the face with his axe. With Splinter knocked out, the Turtles and the remaining Mutanimals attack Slash, then Rockwell attacks as well, taking Raph and leaving the others behind. They return to Shredders lair and tie Raph to a table and he gets brainwashed. The Turtles arrive and defeat Shredder and got Slash, Raph and Rockwell back to their senses. Slash then hurls a statue onto Shredder before retreating with the others.
The Deadly Venom: He is mentioned by Raph after seeing Splinter and Leo sparing.
Dinosaurs Seen in Sewers!:
Annihilation Earth: Slash is in the The Sewer Lair recovering from the events of Dinosaurs Seen in Sewers!. Soon, he and the Mighty Mutanimals help out the Turtles and fight the Triceratons in Washington Square Park. He makes damage to the Heart of Darkness, but is trapped in a bubble by a Triceraton officer and killed in the destruction of Earth.
- Rise Of The Turtles (Debut as Spike)
- Turtle Temper
- Panic In The Sewers
- Enemy Of My Enemy
- Operation: Break Out
- Follow The Leader
- Slash and Destroy (Last Appearance as Spike, First Appearance as Slash)
- Metalhead Rewired
- Battle for New York
- Clash of the Mutanimals
- The Deadly Venom (Mentioned)
- Dinosaurs Seen in Sewers!
- Annihilation Earth