Quietus Spike, and Archfiend of Despair

Prerequisites

• Quietus Spike on the battlefield
• Archfiend of Despair on the battlefield
• Quietus Spike attached to a creature that does not have summoning sickness
• An opponent is unable to block and kill the creature with Quietus Spike attached

Steps

1. Deal combat damage to an opponent with the creature that has Quietus Spike attached
2. Quietus Spike triggers, causing the opponent to lose half their life total, rounded up
3. At the beginning of your end step, Archfiend of Despair triggers, causing the opponent to lose life equal to the life they lost this turn
4. The opponent loses the game due to having zero or less life

Results

• Near-infinite lifeloss for target opponent
• Target opponent loses the game