Through the lens of the similarity-attraction principle, we conducted a pair of studies to examine how perceived physical similarity influences the role similarity and ingroup affinity drives malevolent creativity ideation. Study 1 (N = 305) participants were assigned to teams using the minimal group paradigm and then were given a social threat scenario by an avatar teammate of varying physical demographics (e.g., gender, race, age). Findings suggest that ingroup affinity and perceptions of physical dissimilarity motivate harmful ideas for retaliation against the threat. Study 2 (N = 73) used an existing conflict between rival university teams and presented participants with a social threat scenario. Participants interacted with a virtual avatar with varying degrees of similarity to themselves. Results indicate that ingroup favoritism motivated both original and harmful ideas, whereas dissimilarity with a teammate was a stronger predictor of harmful ideas than similarity. These findings are further discussed through the lens of balance theory and attitudinal similarity.