Joy to the world, the tests are run! The result is a spectacular three-minute Portal (opens in new tab) carol built in Source Filmmaker (opens in new tab) by Harry 'Harry101UK' Callaghan. The turrets—including the Animal King, naturally—have come together at this special time of year to spread neurotoxin to the tune of Mykola Leontovych and Peter J. Wilhousky's Carol of the Bells.
Callaghan did the voices and music himself, with turret rigs provided by August 'Rantis' Loolam, which is an exhausting array of talent and an indictment of my own sorry skillset. You can find his YouTube channel here (opens in new tab), and the song is available on Bandcamp (opens in new tab).