Ovinomancer is a special Creature — Human Wizard card from Time Spiral Timeshifted (TSB), collector number 27. Current market price: $0.27 (foil $0.64), TCGplayer market prices via Scryfall.
When this creature enters, sacrifice it unless you return three basic lands you control to their owner's hand. {T}, Return this creature to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.