Galactus, Devourer of Worlds

Ten mana buys three things the game usually charges dearly for and rarely bundles together: an unconditional exile-on-entry, an indestructible 12/12 with flying and trample, and a threat that keeps pointing itself at the largest life total across the table. The exile trigger is the closer's insurance, cleanly removing whatever answer or blocker stands between the cast and the kill, and it fires whether Galactus is hardcast or cheated into play. The Insatiable Hunger clause is where the flavor gets teeth. Instead of the "may attack" freedom a finisher this size would normally get, the card is compelled: it must swing at whoever is highest on life, every combat, dictating your attacks rather than letting you steer them. That compulsion is the price the rate pays for itself, and the release valve is a single named creature, Silver Surfer, Galactus's Herald, whose presence turns the mandatory attacker back into a controllable one. Restriction and narrative sit on the same lever here: the Herald leashes the hunger both mechanically and in story. Absent that leash, the card politicks on your behalf, forcing engagement with the strongest seat whether or not that is where you want the damage to land. Most oversized bombs ask only that you find the mana; this one asks that you accept where it points once you have.