Bad Milo!

Duncan's (Ken Marino) life is tormented by his crooked boss, nagging mother and his wife (Gillian Jacobs). His mounting stress triggers a gastrointestinal reaction. He seeks the help of a hypnotherapist (Peter Stormare), who helps him discover the root of his unusual stomach pain: a tiny demon living in his intestine that, triggered by excessive anxiety, forces its way out and slaughters the people who have angered him. Fearing that his intestinal demon may target its wrath on the wrong person, Duncan attempts to befriend it, naming it Milo and indulging it to keep its seemingly insatiable appetite at bay.