Trypophobia is a revulsion and fear of objects with clusters of small holes – think beehives, ant holes, and in particular lotus seed heads.

British academics Arnold Wilkins and Geoff Cole, who claim to be the first to scientifically investigate trypophobia, believe the reaction to be based on a biological revulsion, rather than a learned cultural fear. In an article, they discussed that the reaction is based on a brain response that associates the shapes with danger. The type of shapes that elicit a reaction were stated to include clustered holes in skin, meat, wood, plants, wounds and bubbles and that observing these shapes made some individuals state that they felt that their skin is crawling, shudder, feel itchy, experience panic attacks, sweat, palpitate and feel physically sick. Some stated reasons behind this fear are that the holes seem "disgusting and gross" or that "something might be living inside those holes".