Four studies investigate a fear of imbalanced minds hypothesis that threatening agents perceived to be relatively mismatched in capacities for cognition (e.g., self-control and reasoning) and emotion (e.g., sensations and emotions) will be rated as scarier and more dangerous by observers. In ratings of fictional monsters (e.g., zombies and vampires), agents seen as more imbalanced between capacities for cognition and emotion (high cognition–low emotion or low cognition–high emotion) were rated as scarier compared to those with equally matched levels of cognition and emotion (Studies 1 and 2). Similar effects were observed using ratings of scary animals (e.g., tigers, sharks; Studies 2 and 3), and infected humans (Study 4). Moreover, these effects are explained through diminished perceived control/predictability over the target agent. These findings highlight the role of balance between cognition and emotion in appraisal of threatening agents, in part because those agents are seen as more chaotic and uncontrollable.