Pareidolia (pron.: /pærɨˈdoʊliə/ parr-i-doh-lee-ə) is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant, a form of apophenia. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records when played in reverse.
The word comes from the Greek words para (παρά, "beside, alongside, instead") in this context meaning something faulty, wrong, instead of; and the noun eidōlon (εἴδωλον "image, form, shape") the diminutive of eidos. Pareidolia is a type of apophenia, seeing patterns in random data.
http://en.wikipedia.org/wiki/Pareidolia