Kono Subarashii Sekai ni Shukufuku wo!: Kono Subarashii Choker ni Shukufuku wo! - An unaired episode bundled with the 9th volume of the light novel.

The party ends up running into Megumin's self-proclaimed rival, Yunyun, during a trip to Wiz's shop. Annoyed at the increased noise level brought on by additional company, Kazuma notices a choker at his feet. After trying it on casually, he runs into big trouble: it's a magical choker designed to make wishes come true, and until his wish does come true, it's going to keep tightening around his neck until he's strangled to death! The others work hard to help make his "dreams" come true so that the choker will come loose, with Wiz offering her thighs as pillows, Darkness doing push ups to make her chest sway, and Megumin and Yunyun engaged in strip rock paper scissors... while Aqua runs errands. But will even that be enough to make the choker come off?

(Source: Crunchyroll)