: The season concludes with the Turtles infiltrating the TCRI building , discovering their origin's link to the Utrom aliens, and Splinter mysteriously disappearing. 2012 Animated Series (Nickelodeon)
This version was designed to be a more .
: It features a darker aesthetic with heavy shadows and no pupils in the Turtles' masks.
: The Turtles celebrate their 15th "Mutation Day" and visit the surface for the first time, encountering pizza and the alien Kraang .
: Reviewers from IGN praised the season for its "fluid, fast-paced" action and its "show within a show," Space Heroes .
The debut season began as a in December 1987, establishing the core "turtle-mania" tropes.
: Shredder, Krang, Bebop, and Rocksteady are introduced as the primary antagonists operating out of the Technodrome .