Sing: Thriller is a short based on the movie Sing and its sequel, Sing 2, and is themed for the Halloween season. And while it is okay, this is something I would expect to see as an extra for a DVD release or Halloween Short compilation with other Illumination movie shorts than a Netflix exclusive.
In this short, themed around Michael Jackson song Thriller, Buster Moon has their Halloween musical. However, afterwards, when the crew go to Clay's Halloween party, Buster Moon sees a news report of a mysterious goo covering the ground after a laboratory explosion. And this goo turns the citizens into zombies who has the urge to dance.
Yeah, this is an okay short, but not one I feel is worthy of being a Netflix film. The one plus to this is that they got some of the actors from the movies to reprise their roles (Matthew McConaughy as Buster Moon, Scarlett Johannson as Ash, Taron Egerton as Johnny, and Tori Kelly as Meena, among examples), while the other characters appear in non-speaking roles. However, the short suffers for being what it is. At 11 minutes, this feels more like it belongs as part of a DVD collection of Illumination's other Halloween shorts based on their animated films rather than as an exclusive to a streaming service like Netflix, as the special feels more like a music video since it is to the tune of the Michael Jackson song. It's okay, and worth watching if you are a fan of the Sing movies or Michael Jackson, but other may want to seek out other movies that are longer and have an actual story.