The line comes from Yu-Gi-Oh, the Japanese manga and anime series centred on the card game Duel Monsters, where Yugi Muto and his alter ego Yami Yugi challenge opponents to duels. 'It's time to duel' became the series' signature invitation to battle, repeated at the start of countless matches throughout the early 2000s anime. Clips of the call later spread across YouTube, TikTok and soundboards as a shorthand for any head-to-head contest, and it remains popular because it instantly frames ordinary competitions as epic, nostalgic showdowns.