The Young Plague Doctor is the main protagonist and villain of Katy Towell's animated You Tube short, The Black Halloween.
Absolutely nothing is know about the girl other than that she wants all the candy during Halloween and would kill for it. On one Halloween night, she dresses up in a plague doctor costume and goes around her neighborhood spraying some kind of poison into the faces of anyone who answers their doors, as well as other trick or treaters, that causes them to vomit black blood and die right away. Apparently, whatever she affects them with is contagious and spreads throughout the entire neighborhood, even killing the paramedics that drove over to save others. The short ends with her riding in a carriage with piles of candy in the back to her house.