Joss Whedon's company that produces (or in buffy's case produced) the shows Buffy the Vampire Slayer and Angel.

A very short clip of a paper cut out of a cartoon monster on a piece of paper being moved across the screen airs after the credits of every episode. Grr Argh. In Buffy's episode "Once More With Feeling," 'Grr Argh' is sung rather than spoken for one final comical effect.

Mutant Enemy inc. got it's name from Joss Whedon's old typewriter, which shared that name.