Mutant Enemy

Background
This is the production company of Joss Whedon, creator of Buffy the Vampire Slayer, Firefly, and Angel. It is named after Whedon's first typewriter he got at 15, as revealed in an interview on disc three of the first season of Buffy the Vampire Slayer.

1st Logo (March 10, 1997-August 12, 2020)
Visuals: In front of a white piece of display board is a paper cutout of an angry-looking monster (animated by Joss Whedon himself) moving from right to left. The text "MUTANT ENEMY INC." is scrawled onto the display board in a "pointy" style.

Trivia:
 * This logo was spoofed in an episode of Robot Chicken, titled "Rabbits on a Rollercoaster", where Joss Whedon guest stars as himself (in doll form). As the Mutant Enemy rips apart the city, the scene cuts to an office where Joss is playing with paper cutouts and an executive says to him, "Come on Joss, that's why you were kicked off Wonder Woman.". To which Joss holds up one of the monsters and says "Grr, argh!"
 * The Buffy the Vampire Slayer episode "Bargaining (Part 1)" references the end-of-credits logo. Tara gives Giles a small rubber monster and says "Grrr. Argghh.".
 * On the 7th season of Buffy the Vampire Slayer, there is a species of ancient vampires called "Turok-Han" or Ubervamps. They look like more detailed versions of the Mutant Enemy.

Variants:
 * On the Buffy the Vampire Slayer episode "Amends", the monster wears a Santa hat. Jingling bells are heard in the background while the monster says his normal line.
 * On the Buffy the Vampire Slayer season 3 finale "Graduation Day (Part 2)", the monster wears a graduation cap.
 * On the Buffy the Vampire Slayer season 4 premiere "The Freshman", as well as "Living Conditions", "The Harsh Light of Day", "Fear, Itself", and "Beer Bad", the logo is cropped for 16:9 aspect ratio, along with the Kuzui Entertainment and Sandollar logos.
 * Starting with the Buffy the Vampire Slayer episode "Wild at Heart", the logo is vertically stretched correctly (to fit the 16:9 aspect ratio) and we see a little more of the lower half of the monster.
 * On the Buffy the Vampire Slayer series finale "Chosen", the monster turns his head and pulls a face at the viewer while moving.
 * On Marvel's Agents of S.H.I.E.L.D., "INC." is replaced with "eTC".

Technique: Motion-control live-action. The "Chosen" variant also uses some traditional animation.

Audio: Joss Whedon saying "Grr! Argh!" in a very unconvincing manner.

Audio Variants:
 * On ABC airings of Marvel's Agents of S.H.I.E.L.D. (also on Fox airings of Firefly and Dollhouse), the audio is cut off by a voice-over and a generic theme.
 * On the entire 1st season and one season 2 episode "Some Assembly Required" of Buffy the Vampire Slayer, the monster says his line two pitches lower.
 * On the Buffy the Vampire Slayer season 2 premiere "When She Was Bad", the very last note of the show's theme song is played at the beginning before the monster says his line comes up.
 * On the Buffy the Vampire Slayer episode "Becoming (Part 2)", the monster says "Ooh, I need a hug!"
 * On the Buffy the Vampire Slayer episode "Once More, with Feeling", the monster sings the line in a falsetto.
 * On the Buffy the Vampire Slayer episode "Storyteller", the monster sings "We are as Gods!"

Availability: It appeared on Buffy the Vampire Slayer and its spin-off, Angel, the short-lived cult hit Firefly, and Dollhouse. It was also seen on Dr. Horrible's Sing-Along Blog and Marvel's Agents of S.H.I.E.L.D.

2nd Logo (April 11, 2021-)
Visuals: Just a close up shot of Joss Whedon's first typewriter, with the "7" and "&" keys slightly visible. On the typewriter is a piece of black tape with the words "MUTANT ENEMY" on it. There are small tread marks next to the tape.

Technique: A live-action photograph.

Audio: The closing theme.

Availability: It debuted on the HBO series The Nevers.