Kyoukaisenjou no Horizon Special
Genres: Action, Fantasy, Sci-Fi
Type: Special, Episodes: 1
Aired: Dec 21, 2018
Studio: Sunrise
Source: Light novel
Rating: PG-13 - Teens 13 or older
Synopsis:
The Blu-ray Box set of Kyoukaisenjou no Horizon is slated to have an "all-new bonus animation." 

(Source: ANN)