Pareidolia
A type of illusion or misperception involving a vague or obscure stimulus being perceived as something clear and distinct. For example, in the discolorations of a burnt tortilla one sees the face of Jesus Christ. Or one sees the image of Mother Theresa or Ronald Reagan in a cinnamon bun or the face of a man in the moon.
From the Skeptic’s Dictionary. Original post at Language Hat.
This phenomenon is discussed in Atran’s “In Gods We Trust”.