Iago, a mule, was one of Oscar's pets. His first appearance on Sesame Street was in season 23 in Episode 2886. Oscar had gotten him on his trip with the gang to Montana. Getting him out of the trash can was a struggle, but they finally lured him out with carrots.
The donkey also appeared as one of the grouch forest animals in The Adventures of Elmo in Grouchland. He also appeared in CinderElmo and in the nativity pageant in Elmo's World: Happy Holidays!. Iago also appeared in the Elmo's World episode "Birthdays".
He reappeared in 2004 with the name "Eriberto" in a "Global Grover" segment about Mexico. As of this segment, Iago's grouchy eyes were replaced with nicer-looking eyes.