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A blow on the head causes Fred to lose his memory and revert to infancy. Wilma and the Rubbles rush Fred to the office of Dr. Len Frankenstone, a genially mad scientist who has been experimenting with brain transference. Frankenstone figures that the best way to return Fred to normal is to transfer his personality to his house pet Dino, and vice versa. Before the episode ends, everyone in the cast has undergone a bizarre metamorphosis, with Wilma acting like Fred, Barney acting like Betty, and so on into the night!