Professor Thaddeus

 is an owl pet of Beau. As an NPC, is played by Matthew Mercer.

Trivia

 * The name "Professor Thaddeus" originates from a character that Marisha met during Burning Man: "Professor Thaddeus Bubo", proprietor of the "Single Seat Circus". Burning Man is an annual event in the Black Rock Desert of Nevada that experiments in artistic self-expression and radical community inclusion and cooperation.  Matt, Marisha, and Taliesin are well-known for having attended the event each year since before Critical Role first aired.