Malignant narcissism (MN) describes a syndromal configuration at the severe end of pathological narcissism that combines narcissistic personality pathology with antisocial features, ego‑syntonic aggression/sadism, and paranoid tendencies. In isolated, confined, and extreme (ICE) settings—e.g., combat units, polar stations, undersea habitats, and spacecraft—MN traits pose outsized risks to team safety, mission performance, and ethical decision‑making.