The original Teenage Mutant Ninja Turtles was a one-issue comic by Kevin Eastman and Peter Laird--meant to parody popular comic books in the early 80s like Dave Sim's Cerebus, Frank Miller's Ronin and Marvel's Daredevil and New Mutants.
That first issue was a hit at conventions and small runs of comics were printed under Mirage Studios. Well placed ads it became a phenomenon. The Turtle's turned Eastman and Laird into millionaires after they agreed to license the characters to be adapted into a cartoon and action figure line. Leonardo, Raphael, Michelangelo, and Donatello became every kid's hero and "the heroes in a half shell" have been following their master Splinter into battle against petty crooks, Shredder's Foot Soldiers and alien invaders for decades to come--accompanied by April O'Niel and Casey Jones.
The television cartoon started in 1987 as a five part mini-series that was renewed for Saturday morning syndication which expanded into weekdays and an hour long Saturday block on CBS. The cartoon obviously made some changes--becoming less violent and focusing more on humor--giving each of the turtles a color-coded headband and introducing other mutant villains like Bebop and Rocksteady. The popularity of the show spun out into three feature films and pizza-obsessed heroes created a merchandising bonanza; including everything from action figures to video games for the Nintendo, arcades and gameboy. The turtles embarked on a live concert tour due in part to the success of the live action films. Ninja Turtles were everywhere, on t-shirts, sleeping bags, Halloween costumes and most notoriously of all in the form of Chef Boyardee pasta, ice cream bars, Hostess' pudding pies and Nabisco's Royal OOZE Jello knockoff.