Fans of the "Teenage Mutant Ninja Turtles" franchise may want to sit down while reading this. Michael Bay, who is producing the new live action "NInja Turtles" movie, dropped by the Nickelodeon Upfront in New York to talk about the new project. The producer is promising fans an epic return-to-form for the sewer-dwelling masked heros.

But then Bay dropped quite the bombshell: he may be changing up the Turtles' origins.

"These turtles are from an alien race," he said, "And they're going to be tough, edgy, funny and completely loveable."

Until now they were referred to as mutant ninja turtles, not alien ninja turtles. For fans of the comics, the traditional backstory for the "Ninja Turtles" is that they were regular turtles who mutated after being exposed to a radioactive substance.

Needless to say, the fans are not too pleased with Bay for changing the origins of the beloved "Ninja Turtles."

"So will they be changing the title?," asked one Reddit user. "I mean, 'TMNT' doesn't really apply anymore ... Maybe they could be Teenage Alien Interstellar Ninja Turtles?"

However, another Reddit user pointed out that if the Turtles were in fact aliens -- and not nuchuck-wielding ninjas -- perhaps they would have developed more sophisticated weaponry:

"If they're aliens then why would they be ninjas!?!? They would have laser guns and lightsabers and junk! They wouldn't need to be ninjas! Michael Bay is the destroyer of worlds!"

Despite public fan outcry, Bay believes that the alien "Ninja Turtles" could inspire a whole new generation of kids to believe in Leonardo, Donatello, Michelangelo and Raphael again.

"When you see this movie, kids are going to believe, one day, that these turtles actually do exist when we are done with this movie."

Click through the gallery below to see some other outraged fan comments.

The live action "Teenage Mutant Minja Turtles" is tentatively set for a December 2013 release. Watch Bay talk about the film below.