An Ovinomancer is a card in the collectable card game "Magic: The Gathering." The card's function is that it comes into play, turns an opposing active and probably dangerous creature into a harmless sheep, then returns to its user's hand for future play. There is no other known occurance of ovinomancers in any other setting so far.
The word Ovinomancer is a combination of the word "ovine," which refers to sheep, and the suffix "mancer," which often applies to sorcerous abilities, such as the supposed ability of a "necromancer" to commune with the dead.