Arctic Wolves

Cumulative upkeep was Ice Age's attempt to sell power at a discount you pay later, and here is the green draw-a-card version of the bargain: a 4/5 body and a card the turn it lands, with a tax that compounds every turn it survives. The escalation is brutal once you do the math. The first upkeep costs , the second another on top (you pay for each age counter), and within a few turns the wolf is eating your entire mana base alive. The design logic is that you get the front-loaded value (the body and the replacement card) immediately, then choose when to let it die rather than bleed yourself to keep it. That makes the creature less a permanent investment than a delayed-payment cantrip stapled to a wall: you cash the card draw and the blocker for a turn or two, then sacrifice it the moment the upkeep cost outpaces what the body is worth. Cumulative upkeep never found a clean home as a mechanic; the friction it creates (a permanent that actively punishes you for keeping it) runs against the grain of what most players want a creature to do, and Wizards largely retired the keyword after experimenting with it across the mid-90s. Within that experiment, the wolf comes off better than most: the upfront card softens the eventual loss, so the bargain at least starts in your favor before the counters turn it sour.