Theories of embodied cognition hold that the conceptual system uses perceptual simulations for the purposes of representation. A strong prediction is that perceptual phenomena should emerge in conceptual processing, and, in support, previous research has shown that switching modalities from one trial to the next incurs a processing cost during conceptual tasks. However, to date, such research has been limited by its reliance on the retrieval of familiar concepts. We therefore examined concept creation by asking participants to interpret modality-specific compound phrases (i.e., conceptual combinations). Results show that modality switching costs emerge during the creation of new conceptual entities: People are slower to simulate a novel concept (e.g., auditory jingling onion) when their attention has already been engaged by a different modality in simulating a familiar concept (e.g., visual shiny penny). Furthermore, these costs cannot be accounted for by linguistic factors alone. Rather, our findings support the embodied view that concept creation, as well as retrieval, requires situated perceptual simulation.