The aim of this paper is to provide a brief overview of trypophobia, or in other words the fear of "clusters of holes". The first peer-reviewed paper on this curious phenomenon only appeared in the scientific literature about a decade ago, i.e., Cole and Wilkins (Psychological Science 24(10) 1980–1985, 2013), even though it negatively affects a relatively large portion of the general population. After briefly describing the theoretical framework within which most studies of trypophobia are conducted—namely ‘evolutionary psychology’—, we will characterize this phobia and then outline the two main hypotheses likely to explain the disorder: the ‘dangerous animal’ and the ‘skin disease-avoidance’ hypotheses, respectively. As trypophobia is not listed in the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 2013), we will discuss the issue of categorizing this phobia among other specific phobias. The aim of this brief review is therefore to describe the (rare) scientific work that has been done on this a priori innocuous and strange condition, most of which agrees with the idea that the fear of clusters of holes is related to our evolutionary history.