Bad Milo!

Duncan's (Ken Marino) life is a real pain in the ass. Tormented by a crooked boss (Patrick Warburton) and his family, his mounting stress starts to trigger a gastrointestinal reaction. Out of ideas, Duncan seeks the help of a hypnotherapist (Peter Stormare), who helps him discover the root of his unusual stomach pain: a pint-sized demon living in his intestine that, triggered by excessive anxiety, forces its way out and slaughters the people who have angered him. Out of fear that it may target its wrath on the wrong person, Duncan befriends it, naming it Milo and indulging it to keep its appetite at bay.