Aether Helix
Sorcery
Return target permanent to its owner's hand. Return target permanent card from your graveyard to your hand.
Some Quandrix mages prefer to study at twilight, watching their experimental equations trace glowing trails against the encroaching darkness.
Torstein Nordstrand
Rulings
You must choose two legal targets in order to cast Aether Helix. If there are either no permanent cards in your graveyard or no permanents on the battlefield, you cannot begin to cast it.
(wotc • 2021-04-16)
If only one target is still legal as Aether Helix tries to resolve, it will still resolve and perform the appropriate action on the remaining target.
(wotc • 2021-04-16)
Rulings
You must choose two legal targets in order to cast Aether Helix. If there are either no permanent cards in your graveyard or no permanents on the battlefield, you cannot begin to cast it.
(wotc • 2021-04-16)
If only one target is still legal as Aether Helix tries to resolve, it will still resolve and perform the appropriate action on the remaining target.
(wotc • 2021-04-16)