Pin to the Earth

Where most blue answers dispute a creature's continued existence (bounce it, tap it down, draw an aura across its eyes), this one only argues with what the creature does on the swing. A flat -6/-0 empties the power column of almost any attacker without touching toughness, so the host stays on the battlefield, can still block, and keeps any ability that does not key off its power. Six is the number that does the work: large enough to defang the entire commonly seen range of attacker power, so a green stompy beater or a creature whose value was the size of its punch becomes a glorified wall the moment this lands. And because it never lowers toughness, it physically cannot kill. This is containment, not removal, and the distinction is the whole design: you are managing the creature rather than answering it. The cost of that permanence is the cost every Aura pays. A kill spell on the host takes this to the graveyard alongside it, a two-for-one waiting to happen, and a creature that bounces or blinks sheds the enchantment entirely. So the effect is durable against combat math but fragile against anything that removes or relocates the host. What you get is a cheap, clean way to neutralize a single oversized threat for the rest of the game, with the understanding that the creature is still sitting right there.