Teenage Mutant Ninja Turtles IV: The Foot Walks Again

Teenage Mutant Ninja Turtles IV: The Foot Walks Again was a planned sequel to the live-action Teenage Mutant Ninja Turtles live-action films.

Plot
The story would have a fifth turtle join the team named Jack Kirby. It would also included Super Shredder from Teenage Mutant Ninja Turtles II: The Secret of the Ooze, Casey Jones with electric powered fists, and a evil version of April O'Neil.

The only known information of the film was this:

"The fourth live-action TMNT film was pitched and originally scripted as a grittier, less kid-friendly adventure, and to that end Kevin Eastman designed a more brutish, hardcore fifth Turtle, named for the legendary King of Comics (Jack Kirby)."

Why It Was Cancelled
1. The film was cancelled due to the negative reception of Teenage Mutant Ninja Turtles III (1993).

Result

 * 1) The film was permanently cancelled and was rebooted in 2014 with Teenage Mutant Ninja Turtles. The film was followed by a sequel titled Out of the Shadows.