Teleosemantics explains mental representation in terms of biological function and selection history. One of the main objections to the account is the so-called ‘Swampman argument’(Davidson 1987), which holds that there could be a creature with mental representation even though it lacks a selection history. A number of teleosemanticists reject the argument by emphasising that it depends on assuming a creature that is fi ctitious and hence irrelevant for teleosemantics because the theory is only concerned with representations in real-world organisms (Millikan 1996, Neander 1996, 2006, Papineau 2001, 2006). I contend that this strategy doesn’t succeed. I off er an argument that captures the spirit of the original Swampman objection but relies only on organisms found in the actual world. Th e argument undermines the just mentioned response to the Swampman objection, and furthermore leads to a particular challenge to strong representationalist theories of consciousness that endorse teleosemantics such as, eg, Dretske’s (1995) and Tye’s (1995, 2000) accounts. On these theories, the causal effi cacy of consciousness in actual creatures will be undermined.