In the United Kingdom, the series was originally released under the name "Teenage Mutant Hero Turtles" ("TMHT"). This was due to the controversy surrounding ninjas and related weapons such as nunchaku at the time. The intro sequence was heavily edited because of this, replacing the word "ninja" with "hero" or "fighting", using a digitally faded logo instead of the animated blob, and removing any scenes in which Michelangelo wields his nunchaku, replacing them with clips from the show. Scenes of Michelangelo using his nunchaku were likewise edited out of the episodes themselves, which led the American show runners to drop the weapons from the series entirely in the fourth season in order to make the show more appropriate for the international airings. The weapons were replaced with a grappling hook called the "Turtle Line" that served as Mikey's signature weapon for the rest of the show's run. The word 'ninja' was also edited out of any speech within the show, often leading to some awkward sounding dialogue.