Basalt Monolith + Relic Putrescence + Zedruu the Greathearted

Basalt Monolith

Relic Putrescence

Zedruu the Greathearted

How it works

1. Activate Basalt Monolith's first ability by tapping it, adding CCC. Relic Putrescence triggers.
2. Holding priority, activate Basalt Monolith's second ability by paying 3, untapping it.
3. Repeat steps 1 and 2 eight additional times, and then repeat step 1 once. This will result in a total of ten Relic Putrescence triggers.
4. Holding priority, activate Zedruu the Greathearted by paying , donating Basalt Monolith to an opponent.
5. Resolve all Relic Putrescence triggers, causing the opponent who controls it to get ten poison counters. They will then lose the game as a state-based action.

By enchanting your own Basalt Monolith with Relic Putrescence, you turn the artifact's self-contained untap loop into a lethal trap. Because you can repeatedly tap and untap the Monolith in response to its own triggers, you generate a massive stack of poison counters without ever actually passing the turn. Finally, you use Zedruu the Greathearted's donation ability to hand the enchanted Monolith over to an opponent just before those pending triggers resolve, immediately saddling them with the fatal tally of poison counters.