Cast Viscid Lemures by paying {4}{B}
When Viscid Lemures enters the battlefield, Jaws of Defeat triggers.
Holding priority, activate Viscid Lemures by paying {0}, giving it -1/-0 and swampwalk until end of turn.
Repeat step 3 an arbitrarily large number of times.
Resolve the Jaws of Defeat trigger, causing an opponent to lose life equal to the difference between Viscid Lemures' power and toughness.

Target opponent loses the game

Infinite lifeloss for target opponent

Jaws of Defeat

Viscid Lemures

Activate Viscid Lemures's ability.
Crackdown Construct gets +1/+1 until end of turn.
Repeat.

Combos with "Viscid Lemures"