The Dullahan Surpasses Space-Time - S1.E10

Dullahans are demi-humans whose heads are separate from their bodies. Naturally, Tetsuo is intrigued by the unique traits of dullahans, but Kyouko is just as interested in learning more about her own body. Tetsuo has the idea to ask the opinion of someone outside of his own background in biology, so he takes Kyouko to meet Souma, an old college buddy.