Garfield (or The fiend) appears in "Where'd Knuckles Go?!". He is orange with brown stripes and wears a black T-shirt with "I don't do perky" written on it.
He usually talks quietly as Knuckles couldn't hear the fiend and had to look at a note Garfield wrote that said "I'm going to have you for dinner!" which pleased Knuckles until he saw a picture of an enchidna on a plate on it.
He is later easily beat by an angry Sonic. His abnormally loud screams of pain are still not heard by anyone. He reappears in "A Crinkle In Time" when Sonic, Tails, and Knuckles go back in time to the events of "Where'd Knuckles Go?!" . Knuckles remembers he got kidnapped by him and attacks him, kickstarting The Bad Future.
He would appear again in "The Bomb", telling Sonic, Tails, and Knuckles to cut the wire to the bomb, but nobody can understand him because he can't talk.