catoblepas (n.)

a name given by ancient authors to some African animal (perhaps the gnu), late 14c., from Latin catoblepas, from Greek katobleps, from kato "downward" (related to cata-) + blepein "to look," but this might be ancient folk etymology.

A wylde beest that hyghte Catoblefas and hath a lytyll body and nyce in all membres and a grete heed hangynge alway to-warde the erth. [Bartholomew Glanville, "De proprietatibus rerum," c. 1240, translated by John of Trevisa c. 1398]