Mr. Herrera (voiced by Sam Johnson) was the Spanish teacher at Highland High. This meant he taught Daria Morgendorffer - unfortunately for him, it also meant he taught Beavis and Butt-head. When Beavis became the Great Cornholio in "The Great Cornholio", he disrupted class and pissed Herrera off.
He celebrated their apparent demise in "Beavis and Butt-head are Dead".