A chimera (noun and sometimes capitalized) is a fire-breathing she-monster from Greek mythology with a lion's head, a goat's body and a serpent's tail. Chimera has come to describe any imaginary hybrid monster. Chimera is also one of my favorite metaphors describing a illusion, vision or an unfathomable, soul-shaking nightmare. In biology and genetics, the term refers to an individual made of unmatching genetic material; in theory what might happen if an embryo sometime in the early stages of division absorbs another "sibling" embryo. One also thinks of chimeras in regards to conjoined human twins or a cat born with two heads - phenomena stranger than fiction. If that's not an image for Halloween, I don't know what is.