Humongous Chicken is a chicken who pestered Elmo as he tries to get to Huxley's castle to retrieve his stolen blanket in The Adventures of Elmo in Grouchland (where he was first a giant, slow-witted chicken). He got sent by Huxley and Bill to defeat Elmo and mistakes Elmo for a worm. However, upon hearing Elmo sing "I'm a Little Teapot" to prove that he isn't a worm, the Humongous Chicken then thinks that Elmo is a teapot and declares that he can't have tea. He hasn't had his "din-din" yet and then tosses Elmo off the tree branch.
The chicken is a normal-sized hand puppet, but is superimposed over the landscape to appear bigger. He is one of Dave Goelz's few Sesame characters.
Humongous Chicken was a hero on the episode "Super Chicken" to help with situations as a super hero, but on part of that episode, he becomes greedy enough to selfishly eat all of the popcorn out of children's bags and the bowl as well so that way there isn't any popcorn left and insults towards everyone including Super Grover. The vicious behavior for the chicken where the chicken is out of control is not like the behavior he engaged towards Elmo in his prototype appearance.
Birdwalk Empire on the other hand is in a team of chickens to fight with the ducks on how they walk and what they're speeches are until that situation against these things have been handled by Agent Van Cuckoo to make them do it together and fairly.
While not nearly evil on the Elmo the Musical sketch "Bird the Musical" for the song "Play Ball" and after he catches Mama Bird's egg, he confuses Elmo into thinking that egg is a baseball even though not fooled that it is oval shaped and the baseball is round. He then gives her egg back after the chicken player sorts it out.
A similar variation of the puppet has later been used on Sesame Street, such as for Super Chicken (with feminine eyelids). It has subsequently been used for multiple other characters on Sesamstrasse. The variant without the eyelids can also be found on Elmo the Musical and on The Furchester Hotel.