Splinter is the mutant rat sensei and adoptive father of the Ninja Turtles. In most incarnations, Splinter is a mutated or reincarnated martial artist Hamato Yoshi; in others, he was Yoshi's pet rat. Splinter, often referred to as Master Splinter by his students, is a fictional character from the Teenage Mutant Ninja Turtles comics and all related media. Price: $4.00 + $3.99 shipping: This fits your . A mutant rat, he is the martial arts and ninjutsu instructor of the Turtles, as well as their adoptive father. Make sure this fits by entering your model number. 5 INCH Splinter Rat Sensei Turtle TMNT Teenage Mutant Ninja Turtles Removable Peel Self Stick Wall Decal Sticker Art Kids Decor Boys Room 3 1/2 x 5 inches by WiggleWalls. In the 1987 cartoon , Splinter (voiced by Peter Reneday ) is Hamato Yoshi , mutated into a mutant brown rat alongside the Turtles, who he rescued from accidentally getting dropped down a storm drain after moving to New York.