Ravenous Necrotitan

A 6/6 body arriving at four mana ought to carry a leash, and the leash here is an entry toll: sacrifice a creature unless an opponent is already three poison counters deep. That inverts the usual poison payoff. Where most infect and toxic cards reward you for stacking counters on the way to ten, this treats a specific threshold as a gate, then hands you an oversized attacker for having cleared it. Below that count, it is a beater that eats one of your own creatures the instant it lands, which turns the sacrifice into a resource question rather than pure loss: feed it a token or a spare piece of fodder and you have paid nothing you were not already spending, though with no flash the trade happens during your own development, not in response to combat. The Corrupted clause reads as a reward gate rather than a drawback, making the counter-count matter at a moment when poison decks are otherwise just watching a number climb. The tension is that the deck best equipped to satisfy the condition wants a big ground beater least, while the deck that most wants the body has to build toward a poison count it does not otherwise need. That mismatch is the whole character of the card.