Tranquilize

Stun counters reframed what "tapping down" can buy. Old-school tappers like Icy Manipulator or Frost Titan bought a single untap step of denial: the creature came back the following turn, and you paid mana again to keep it home. Three stun counters instead sell a three-turn absence for a flat two-mana sorcery. The permanent stays tapped through three of its controller's untap steps, each step burning a counter instead of freeing the creature, which turns a temporary tempo play into a semi-permanent removal effect against anything without a way to untap on its own or blink itself. That is the design bargain: the creature is not dead, so it dodges "destroy" hate and can still be sacrificed or reanimated, but for three of its owner's turns it is functionally off the board as an attacker, blocker, or tapper. The sorcery speed is the honest cost. This cannot ambush an attacker or answer a flash threat at the last moment; it has to be spent on the main phase, committing to lock down something already on the battlefield rather than reacting to what an opponent is about to do. It is blue getting a durable answer to a single large creature without leaving its color pie, trading the reach and permanence of true removal for a predictable, counter-based clock that ticks the threat back online three turns later.