A serpent with two heads, and eyes that glow. From the Greek "goes both ways."
If cut in half, both halves will rejoin. If the heads hold each other, the amphisbaena can roll along like a hoop. Wearing a live amphisbaena is said to help in pregnancy, and wearing a dead one will help rheumatism.
the amphisbaena has a twin head, that is one at the tail end as well, as though it were not enough for poison to be poured out of one mouth."
A smaller kind of Serpent, which moveth forward and backward, hath two heads...Which double formations do often happen unto multiparous generations, more especially that of Serpents; whose productions being numerous, and their Eggs in chains or links together (which sometime conjoyn and inoculate into each other) they may unite into various shapes and come out in mixed formations." (Pseudodoxia Epidemica)
