This dazzling loop uses Doc Aurlock, Grizzled Genius as a relentless cost-reducer, dropping the normal exile-casting fee down to zero so you can recycle your legendary avatars for free. When Aang, the Last Airbender enters the battlefield, he whisks away Appa, Steadfast Guardian into exile using his airbend mechanic, setting up an endless chain. Appa then returns the favor upon re-entry by exiling Aang right back, creating a continuous ping-pong of entering and leaving the battlefield. With Doc Aurlock footing the bill, every iteration of recasting these permanents from exile triggers Appa's secondary ability to flood the board with an endless army of 1/1 white Ally creature tokens while driving your storm count through the roof.