Austin Michael Costello is a puppeteer and builder who has served as an assistant Muppet performer for Sesame Street since 2015.
In season 46, he manipulated the arms of the Bagels and Locktopus in episode 4620. In season 48, Costello right-handed for Big Bird in episode 4810. Costello has also done a couple turns as the back end of Mr. Snuffleupagus, including the Sesame Street Mannequin Challenge video, and for a rehearsal for the 2019 Macy's Thanksgiving Day Parade (filling in for Bryant Young in the latter).
Costello began working at the Jim Henson Company in 2013 as an intern at the Henson Archives and, in the following year, worked as an assistant in the New York workshop. Among his duties was writing entries for the Jim Henson's Red Book blog and for The Dark Crystal website. Costello is a graduate of The University of Connecticut's Puppet Arts Program and has performed at The National Puppetry Conference. He was also one of the cast members in Martin P. Robinson's off-Broadway musical All Hallows Eve, which played for a limited run during Halloween 2019.