Theobald Brooks-Lengyel, born in 1970, joined Mr Bungle while attending Eureka High school in 1986. He played alto saxophone on all Mr Bungle demos leading up to the 1991 self-titled debut, on which he played alto & baritone sax. On 1995's Disco Volante he again played sax as well as clarinet & flute. Live with Mr Bungle he was known to also play trombone & keyboards. Unlike Mr Bungle's other members, Theo was never really involved with any other side projects. In 1999 Theo Lengyel was fired from Mr Bungle, with the band citing creative differences.

When asked, Trevor Dunn had this to say:

"We kicked Theo out because his tastes and abilities as a musician where not progressing at the same rate as the rest of the band. It was a difficult, painful experience. Nothing personal"

Nobody has seen nor heard from him since.