C.K. voiced "The Horrifying Sweaty One-Armed Monstrosity" in a pair of Gravity Falls episodes – 2015's "Weirdmageddon: Part 1" and 2016's "Weirdmageddon: Part 3," the Hollywood Reporter writes. The comedian's name was also removed from the show's credits.
"The role was rerecorded approximately one month ago and new versions of three episodes are now on the Disney XD schedule around the world," a Disney Channels spokesperson said. "Series creator and executive producer Alex Hirsch is now credited as playing the character."
Universal Pictures and Illumination also previously announced that C.K. would not reprise the voice role of the dog Max in the upcoming animated kids movie The Secret Life of Pets 2, due out June 2019; C.K. voiced the lead role for a canine specifically designed after the comedian in the original 2016 film.
Compare the C.K. episode of Gravity Falls with the redubbed version below: