McCay began work that May on his next animated film, "How a Mosquito Operates", based on a "Rarebit Fiend" episode from June 5, 1909, in which a man in bed tries in vain to defend himself from a giant mosquito, which drinks itself so full that it explodes. The animation is naturalistic—rather than expanding like a balloon, with each sip of blood the mosquito's abdomen swells according to its body structure. The film was completed in January 1912, and McCay toured with it that spring and summer.