The eighth season of Teenage Mutant Ninja Turtles aired in 1994. From this point onwards, the show was retooled into a more action-based series. Among the changes, the tone of the show became darker, the art style changed significantly, and many of the previous notable characters were removed. There was also a new title sequence and completely new theme song. These final three seasons are known as the "Red Sky episodes" amongst fans, because the sky was constantly portrayed as red, instead of the usual blue. The Technodrome is now in Dimension X, while Krang, Shredder, Bebop and Rocksteady are stranded on Earth.