Twinflame + Priest of Urabrask + Fork + Ardent Elementalist

Twinflame

Priest of Urabrask

Fork

Ardent Elementalist

How it works

1. Cast Twinflame by paying 3, targeting any two creatures.
2. Holding priority, cast Fork by paying its mana cost, copying Twinflame, with the copy targeting Priest of Urabrask and Ardent Elementalist.
3. Resolve the copy of Twinflame, creating a token copy of Priest of Urabrask and Ardent Elementalist with haste.
4. When the Priest of Urabrask and Ardent Elementalist tokens enter, they trigger.
5. Resolve the Priest of Urabrask trigger, adding .
6. Resolve the Ardent Elementalist trigger, returning Fork from your graveyard to your hand.
7. Repeat from step 2.

This loop relies on a brilliant chain of recursion fueled entirely by your own spells and creatures. By kicking things off with Twinflame to target a couple of creatures, you then respond with Fork to copy it, aiming the copy at Priest of Urabrask and Ardent Elementalist. When those token copies enter the battlefield, Priest of Urabrask immediately replenishes your mana with a massive burst of red energy, while Ardent Elementalist neatly fishes Fork right back out of your graveyard. You can then recast Fork targeting the original Twinflame copy process over and over, generating an unbounded army of hasty attackers, infinite mana, and endless storm and magecraft triggers.