Smothering Abomination

The mandatory upkeep sacrifice is the load-bearing line, and it points in two directions at once. Most sacrifice payoffs are passive: they reward you when you happen to throw a creature away, leaving the engine idle if your deck has nothing to feed it. This one forces the issue. Every turn you keep it, you must sacrifice a creature, and that compulsion guarantees the card-draw trigger keeps firing. The design hands you a built-in clock and dares you to outpace it. Without a steady supply of expendable bodies (tokens, recursion, creatures with their own death payoffs), the upkeep tax eats your board and eventually the Abomination itself once nothing else is left to feed it. With that supply, the draw ability rewards not just the forced upkeep sacrifice but any creature you sacrifice, so a sacrifice outlet on the table lets you convert bodies into cards at your own pace instead of waiting on your upkeep for each one. That is the tension the four-mana flyer is balancing: a 4/3 evasive body that refuels you relentlessly, attached to an obligation you cannot turn off. It belongs in decks built to convert creatures into resources rather than decks that merely tolerate losing them, which is exactly the line between a draw engine and a slow self-mill.