Shampoo's Red Thread of Dread!

Shampoo's Red Thread of Dread!

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S4 E20: Shampoo obtains the "Red Thread of Fate," which can make anyone fall head-over-heels in love with the user. She quickly ties it to Ranma's pinky. Ranma immediately starts acting weird and can't keep himself away from Shampoo. He even starts talking about marriage!