Studio 4C provided additional animation services for this episode, most likely working on the brief anime-style action scene. Tokuyuki Matsutake was responsible for character designs and direction. Unfortunately, no KA list was provided on Studio 4C's side but I won't be surprised if Matsutake did some of the action at least.

Holy is this real life?

That's awesome!

The Amazing World of Gumball. Probably the animated series with the greatest variety of different animation styles. In the Universe.