1x155 - Urusei Yatsura

Episode one of a two-Episode Serial. Shutaro is forced into an arranged marriage with the heavily armored Asuka Mizunokoji of the Mizunokoji clan, who've been mortal enemies with the Mendou clan for generations. While Shutaro wants nothing to do with Asuka, Ataru (of course) wants this armored girl for himself. A girl who, apparently, has never met a man before, much less one outside of her armor. At episode's end her armor is removed via Lum shocking her with Ataru clinging to her, revealing her true appearance. Cherry ends the episode, breaking the fourth wall as he tells the audience to turn in next time for the conclusion.