Isekai Quartet is a popular chibi-style crossover anime that features characters from several 'Isekai' (another world) light novel series, including Overlord, Konosuba, Re:Zero, and The Saga of Tanya the Evil. The meme originates from the show's premise where characters are transported to a high school world after pressing a mysterious red button. Memes usually focus on the hilarious interactions between clashing personalities—like the overpowered Ainz Ooal Gown meeting the perpetually unlucky Kazuma. It is frequently used to represent different friend groups merging, the chaos of group chats, or the 'cross-pollination' of different internet subcultures.