Abstract
It is common to think that it’s possible for entities to spatially coincide in multiple ways: with overcrowding, and without overcrowding. Typically, we can distinguish between these by claiming that uncrowded spatial overlap involves a sharing of parts, and crowded spatial overlap does not. However, if we think that mereologically unusual entities, such as extended simples or some kinds of gunk, can also spatially overlap in crowded and uncrowded ways, we lose the ability to distinguish between those varieties of spatial overlap via appeal to shared parts. Thus, we should either reject the possibilities that generated this difficulty, or we must look for an alternative explanation of these varieties of spatial overlap.