Professional debunker Michael Shermer has an alternative theory for alien abduction experiences:

People who claim to have been abducted by aliens hallucinated their experiences.

Shermer's reputation is also impressive. He is director of the Skeptics Society and has proven that many claims about paranormal phenomena are either deliberate hoaxes or normal events that have been innocently mistaken for something unusual. In his article in this anthology, Shermer explains how many "abductees" could really be hallucinating their experiences. To support this claim, he discusses an experience he had in which he believed aliens were impersonating his road crew during a long bicycle race.