Tenchi Universe - Season 1 Episode 10 No Need for an Arch Rival!
Overview: A ruthless interstellar bounty hunter, Nagi, arrives on Earth to claim the price on Ryoko's head. She kidnaps Tenchi and challenges Ryoko to a showdown to claim him back. However, she doesn't reckon on her spaceship cabbit, Ken-Ohki, falling in love with Ryo-Ohki!