To feel nervously and apprehensively “creeped out” is a familiar emotional state, but its cause—what makes something or someone “creepy”—is poorly understood. A recent evolutionary account of creepiness suggests that the emotion arises from a perceived “ambiguity about the presence of threat” (McAndrew and Koehnke 10). However, not all ambiguous threats are perceived as creepy. This article argues that specifically creepy threats arise from disrupted mentalization, by which is meant difficulties in apprehending the mind of another being in such a way as to make that being seem threateningly unpredictable. The authors propose that this explanation of creepiness also explains “the uncanny,” a concept that is closely related to creepiness and to which a much older and larger research literature attaches. Finally, it is suggested that the present account can make sense of some iconically creepy figures of horror fictions, including zombies, ghosts, and ominously unhuman children.