Teenage Mutant Ninja Turtles Season 1 -

: The Turtles celebrate their 15th "Mutation Day" and visit the surface for the first time, encountering pizza and the alien Kraang .

: It features a darker aesthetic with heavy shadows and no pupils in the Turtles' masks. Teenage Mutant Ninja Turtles Season 1

: 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) : The Turtles celebrate their 15th "Mutation Day"