Fenrir is the giant wolf of Norse mythology, a figure who has appeared in countless games, stories and memes, and the Spanish title 'riendo' simply means laughing. The exact source of this particular laugh is unclear, so it is best treated as a fan-made or ripped game clip rather than an official line. It circulates mainly in Spanish-speaking meme and gaming communities, where short villain laughs are a staple reaction sound. Its staying power comes from versatility: a dark chuckle fits betrayals, comebacks, trolling and plot twists in almost any edit.