Nikola Messla

Nikola Messla is a Grouch professor at "Putrid University" (P.U.) who appears in episode 4260 of Sesame Street.

Oscar takes the online Grouchology class from the college, learning how to be a Grouch scientists. Messla instructs him via a webcam, aided by the Pesties.

His name is a reference to Nikola Tesla, a well known scientists and inventor.