Michael Clarke Duncan was an American actor, best known for his breakout role as John Coffey in The Green Mile, for which he was nominated for an Academy Award and a Golden Globe. He is known for his very deep voice.
In "The Tan Aquatic with Steve Zissou", he voiced Fozzie Bear during the "Wrong-sounding Muppets" cutaway and during the last scene. However Frank Oz was still alive when the episode first aired, and so a voice change would not be necessary.
In "You May Now Kiss the...Uh...Guy Who Receives" he voiced a boy high on mushrooms.
In the Stewie Griffin: The Untold Story segment "Stu & Stewie's Excellent Adventure" he voiced the stork that, instead of bringing a woman the baby, tried seducing her into making it together with him.