Magar of the Magic Strings + Chance for Glory + Day's Undoing

Magar of the Magic Strings

Chance for Glory

Day's Undoing

How it works

1. Cast Chance for Glory by paying its mana cost, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
2. Activate Magar by paying 1, noting Chance for Glory and putting it face down on the battlefield as a 3/3 creature.
3. Activate Magar by paying 1, noting Day's Undoing and putting it face down on the battlefield as a 3/3 creature.
4. During your next turn, deal combat damage to an opponent using the face down creatures that have Chance for Glory and Day's Undoing noted. The creatures trigger.
5. Resolve the first trigger, casting a copy of Chance for Glory without paying its mana cost. Resolve the copy, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
6. Resolve the second trigger, casting a copy of Day's Undoing without paying its mana cost. Resolve the copy, causing you to end the turn. This will prevent the Chance for Glory trigger from causing you to lose the game.
7. Repeat from step 3.

Magar of the Magic Strings serves as the ingenious puppet master of this loop, turning devastating spells into deadly 3/3 combat combatants in your graveyard. When these face-down creatures successfully connect with an opponent, they trigger to cast copies of their noted spells for free. Chance for Glory grants you the precious extra turns needed to keep the engine running, but it comes with a lethal delayed trigger that would normally make you lose the game at that turn's end step. Day's Undoing elegantly sidesteps this death sentence by abruptly ending the turn upon resolution, sweeping away the pending loss condition before it can ever trigger and trapping your opponents in an endless, unbreakable cycle of extra turns.