Leroy was a donkey who appeared in The Muppet Musicians of Bremen.
After he runs away from his mean owner Mordecai Sledge, with a tuba around his neck and a wagon full of stolen musical instruments, Kermit convinces Leroy that he should become a traveling musician. The biggest motivation for Leroy to follow his dream is the love and affection that traveling musicians tend to receive. Even when Leroy and his newfound friends find their mean owners' secret hide-away, Leroy manages to convince the gang that there's a nice family inside.
Two Leroy puppets were used in the special: a hand puppet (with an eyebrow mechanism and an upper lip that moves over his front teeth), and a full body marionette for wide shots.
Leroy was the only character on the special to interact with Kermit.
Unlike the other animals (T.R., Catgut and Rover Joe, who all appeared on The Muppet Show), Leroy did not appear outside the TV special. He did, however, make a cameo appearance alongside his Muppet Musicians bandmates in the first issue of Muppet King Arthur.