The rather questionable answer is "Hedgehog Pie." How a hedgehog is "stingy" is beyond me, but "pie" is the only consumable item that appears as the second word of a monster's name. Pies don't generally improve with age - actually, they tend to go bad - but the number "pi" does become more accurate as you use more decimal places. Alternately, as the concept has grown older, we've found more accurate decimal places for it.