Etrata, the Silencer + Lithoform Engine + Return the Favor

Etrata, the Silencer

Lithoform Engine

Return the Favor

How it works

1. Deal combat damage to an opponent using Etrata, triggering its ability.
2. Holding priority, activate Lithoform's Engine's first ability by paying 2 and tapping it, copying Etrata's trigger.
3. Holding priority, cast Return the Favor by paying 1, choosing its first mode, copying Etrata's trigger.
4. Resolve all Etrata triggers, exiling three creatures an opponent controls and putting hit counters on them, and then causing that opponent to lose the game.

This lethal loop relies on exploiting Etrata, the Silencer's combat damage trigger by instantly multiplying it before she can shuffle herself away. When she connects with an opponent, her ability triggers to exile a creature and place a hit counter, but by responding with Lithoform Engine's first ability and casting Return the Favor, you can copy that single trigger multiple times in one fell swoop. Because Etrata's win condition simply checks the number of exiled cards with hit counters owned by that player, chaining these extra copies together instantly racks up the required three counters and abruptly ends the game.