From Muppet Wiki

Willy was the hot dog vendor on Sesame Street, appearing sporadically between the 1970s and the early 90s. He appeared as early as the second season premiere. Willy also appeared in Follow That Bird.

Trivia

• A Muppet version of Willy appeared during the mid-70s, made from the Green Anything Muppet.

• Willy wears a yellow feather in his hat; Kermit Love built the original Big Bird body.