The Not-Too-Late Show with Elmo
Mama Bear and the Monsters is a Sesame Street band that first popped up on the show in Episode 4913. In the episode, they are presented as a jazz quartet, with Mama Bear on drums, Louie on saxophone, Freddy on piano, and Herry Monster on bass. Their performance inspires Elmo, Abby, Ernie, and Bert to form their own pretend band. The band was mentioned on the show later in Episode 5106, where they are said to be playing in a holiday concert.
The group, without Louie, was later promoted to a much more prominent role as the house band for The Not-Too-Late Show with Elmo, but were phased out for season two.
Elsewhere, Mama Bear and Herry Monster (playing their same instruments) appeared throughout Sesame Street's 50th Anniversary Celebration, providing musical accompaniment to many scenes and musical numbers. Their band replaces the other monsters with Ovejita on guitar and Hoots the Owl on saxophone.