means the war horse of alexander the great, famous for being unrideable by anyone until a boy noticed it was just scared of its own shadow.

from greek for ox-headed, either from a white marking on its head shaped like one or its sheer bull-like build; alexander tamed it around age 12 by turning it away from the sun so it stopped spooking at its own shadow, and philip ii reportedly told him to find a bigger kingdom because macedon was too small for him.