Parasitic Implant

The trade this Aura offers is brutal and slow at once: four mana and a card to delete a creature, but not until your own upkeep comes around, and the victim's controller is the one pulling the trigger. That delay is the whole negotiation. A removal spell answers a threat now; this answers it next turn, which means the enchanted creature gets one more crack at attacking, blocking, or being sacrificed out from under the effect entirely. The compensation built into the deal is the 1/1 Phyrexian Myr you receive, a small artifact body that arrives once, when the sacrifice resolves and the Aura itself falls to the graveyard alongside its host. Read it carefully and the recasting becomes the design idea: "destroy" rephrased as "convert into a token you control," a single body left behind for the sacrifice outlets and artifact-matters engines that turn dead creatures into resources. It also explains why the timing sits where it does. Were the sacrifice immediate, this would simply be overpriced spot removal; pushing it to upkeep and handing the controller the act of sacrificing keeps it an enchantment rather than a hard answer, while opening a full turn for the opponent to respond, bounce it, or feed the doomed creature to something better. What four mana buys here is not speed but a delayed certainty plus a Myr, removal that pays out a body for the decks that want one.