am·phis·bae·na 
(ăm′fĭs-bēnə)
(ăm′fĭs-bēnə)n.
A mythical serpent or winged creature having a head at each end of its body.
[Middle English amphibena, from Latin amphisbaena, from Greek amphisbaina : amphis, both ways (from amphi-, amphi-) + bainein, to go; see gwā- in the Appendix of Indo-European roots.]
am′phis·baenic adj.