Kinoko Ningen no Kekkon

Our story begins on an all-woman planet of intelligent fungi, where Ariella and Eriella are about to get married! But they've got a long road ahead of them: illness, surgery, and even a dastardly royal plot that seeks to split them apart. Is their love strong enough to weather any storm? This offbeat, adorable, and dramatic one-shot is sure to please fans of yuri, monster girls, and enduring romance!

(Source: MangaUpdates)