Extra: HEY! Butts!

The first OAD of the anime adaptation of That Time I Got Reincarnated as a Slime.

Synopsis
An OAD about the Sumo competition that held at Tempest for the first time, suggested by Rimuru.

Trivia

 * This OAD is bundled with the special edition of Manga Volume 13.
 * This episode was originally scheduled to release on March 2019 but was delayed to December 2019.