The third season of Isekai Quartet.

The button appeared out of nowhere. Was it a trap or the start of something new? The crews of Re:ZERO, Overlord, KONOSUBA, and Saga of Tanya the Evil got stuck in another world’s class! Now, more new characters join the series, including Alpha and Shadow from The Eminence in Shadow. See what adorable chaos they’ll get up to in this collection of shorts!

(Source: Crunchyroll)