Rimescale Dragon

Tapping a creature is a temporary inconvenience; keeping it tapped forever is a different category of card. The third line is what converts a soft tempo play into a hard answer: a creature with an ice counter never sees its untap step again. One activation and the opponent's biggest blocker becomes a paperweight while the 5/5 flier carries the game over the top in the air. The snow mana requirement is the cost that pays for the lock. Without a deliberately snow-heavy base the ability is dead, and even with one you spend two generic plus a snow source every turn to expand the prison one creature at a time. That throttle is what keeps a repeatable, no-restriction soft lock from being oppressive: it grinds the opponent's board to a halt creature by creature rather than all at once. The design exploits the gap between "tapped" and "stays tapped," the difference between a single tap-down poke and a permanent neutralization, a trick that needs a permanent counter to enforce rather than a one-turn effect to fade. The flier alone would be a serviceable finisher; the ice-counter engine is the part that promotes the Dragon from a control deck's top end to its actual win condition, suffocating an aggressive board one creature at a time while five power overhead handles the clock.