As Michael Bay's new Teenage Mutant Ninja Turtles adaptation gets set to hit theaters – only seven years after the last such film – audiences are left gawking at the rather monstrous new forms for the team.

Yet behind their slightly scary exteriors, they're the usual suspects – Leo, Mikey, Raph, Don. For 30 years, the turtles have fought crime in comics, films, and TV shows, just the four of them.

But there were not always four. For a time – on a TV show most fans would like to forget – there was a fifth. Even more monumentally, this turtle was female. Her name was Venus de Milo. And she has been relegated to the trash bin of TMNT history for over a decade.

It's a Man Turtle's World

Since the franchise's debut in 1984, there have been four turtles on the main team: Leonardo, Michelangelo, Raphael, and Donatello. The turtles were each named after a legendary artist – and, of course, all male. Though there were other mutants in the TMNT universe – including the female Mona Lisa, a mutant lizard – the only other turtle for the franchise's first decade or so was the villainous Slash, also male.

That all changed with Ninja Turtles: The Next Mutation, a Fox Kids series that ran for one season in the late '90s. That series introduced Venus, notably the only turtle named after a work of art instead of an artist. She was supposedly found in the same way as the rest of the turtles – in the sewers, exposed to a mutating agent – but the male turtles' mentor, Splinter, didn't take her as he did with the others.

Venus – then going by Mei Pieh Chi – was raised in China by Chung I, a magician. She learned his craft, then went to New York City and joined up with the other turtles. She took the name Venus and fought with them.

Rather unluckily for her, Venus was introduced in one of the most critically reviled incarnations of the show. The Next Evolution was low-budget, and it showed. When your series has a crossover episode with the Power Rangers and yours come off looking like the cheaper property, you know things have gotten bad.

Continuity was also a problem for The Next Evolution, which had ignored the long-established fact that the main turtles were brothers. That, of course, made it all the easier for fans to ignore entirely.

Erasure from Canon

Unsurprisingly, The Next Evolution was cancelled after one season. There was an informal "second season" that consisted of letters 'written by' each of the turtles. The letters detailed the remaining adventures for the team – until the end, when suddenly, Venus was gone. There was no explanation given for her sudden disappearance.

It was the first in a series of acts designed to purge Venus from the TMNT canon. Venus' series of letters, called "Venus' Venerations," were reportedly pulled from the site after a few years. (The letters are now completely gone, as the site has been revamped for the new movie.) But series creator Peter Laird apparently considers Venus enough of an embarrassment to forbid her from cinematic adaptations.

"There's absolutely no mention of Venus de Milo, the female Turtle," 2007's TMNT director Kevin Munroe said in an interview before the film's release. "You can't even joke about that with Peter. It's just one of those things that he hates with a passion."

To date, Venus' only appearance has been in The Next Evolution canon.

The Future of Venus

Notably, the TMNT universe hasn't had a female turtle since Venus – and at least one comic writer, Gary Carlson, has been told not to introduce any others. So it would seem that removing Venus from continuity isn't just about expunging The Next Evolution from the franchise's history.

It's hard to lament the absence of a character who only existed for a year of a franchise's three decade-long history. Yet a handful of fans have called for the current Nickelodeon animated adaptation of TMNT to bring Venus back. (There's also a petition to keep her off the show, but it has even less support.)

There has been one 'female turtle' in a comic since Venus' first appearance, however. In Teenage Mutant Ninja Turtles Volume 3, Issue 12, printed while The Next Evolution was still airing, Michelangelo introduces his new girlfriend to the other turtles. A hero crossing over from another comic, Vanguard, yells at the girlfriend and causes 'her' to transform back into Lurch, a monster who changed shape into a female turtle.

It's hard out there for female Teenage Mutant Ninja Turtles: you're either actually a monster, or you get erased from ever existing.