Doctor Harrison Horseberry was a male Human Starfleet officer who served as the chief medical officer of Starbase 80 in the late 24th century. Station commander Kassia Nox affectionately considered him one of her "biggest weirdos" and thought it remarkable that he was of British descent.
Horseberry was once infected by a Tarchanne parasite from sharing a toothbrush with a colleague. Though the metamorphosis was halted, the left side of his body remained partially transformed into a Tarchanne. Thereafter, he scanned everyone for the parasite, "just for fun".
In 2382, Nox consulted Horseberry regarding a cognitively debilitating "curse" spreading among crew visiting from the USS Cerritos. Though Horseberry could detect no cause for the ailment, Nox realized that it was spreading through combadges. Horseberry then accompanied her, Lieutenant jg Beckett Mariner, and Chad to the Cerritos, where they tracked the source of the malady to Cetacean Ops and Lieutenant Matt, who had been possessed by the anaphasic lifeform Clem. After Clem seized Nox and Mariner, Horseberry forced Matt to vomit it up by hitting him in the head with a pool skimmer, then contained it by putting a bucket over it. Horseberry later constructed a stable vessel for Clem to inhabit. (LD: "Starbase 80?!")