In a nutshell:
- During the untap step, before any permanents are untapped, all permanents with phasing “phase out” and all permanents that are phased out “phase in.” These actions happen simultaneously. A phased out permanent remains on the battlefield, but is treated as though it doesn’t exist (with a few exceptions) for all game purposes.
- Phasing happens during the untap step. If that step is skipped, no permanents will phase in or out that turn.
- The phasing event is a turn-based action like untapping or declaring attackers. It doesn’t use the stack; it just happens. It’s not possible for players to “respond to” a permanent phasing in or out.
- Phasing in or out doesn’t count as an permanent entering or leaving the battlefield, so abilities that look for those conditions will not apply.
- If a permanent phases out, any Auras or Equipment attached to it will phase out along with it. This is called phasing out “indirectly.” If a permanent phases out indirectly, it will phase in attached to the same object it was attached to when it phased out.
- Because phasing out doesn’t count as leaving the battlefield, any counters that were on the object will remain on it. Any linked abilities involving that object will not reset, and any choices made as the object entered the battlefield or was cast as a spell are retained.
- If a player controls a permanent that phases out, that permanent will phase back in during that player’s next untap step, regardless of whether that player is that permanent’s owner.
Q: Why does Teferi’s Isle work? Since it enters the battlefield tapped, doesn’t it just always phase in tapped also?
A: Phasing in does not count as entering the battlefield, so Teferi’s Isle does not phase in tapped. Even if it did, the phasing event happens before untapping for the turn does, so Teferi’s Isle would get untapped anyway.
Q: Amy controls two Sandbar Crocodiles, one of which is phased out. She plays Collective Unconscious. How many cards does she draw?
A: Only one. A permanent that’s phased out is treated as though it doesn’t exist. As such, when the game is counting how many creatures Amy controls, it only sees one Sandbar Crocodile, so she only draws one card.
Q: Amy plays Sandbar Crocodile and then Savor the Moment. Can she attack with Sandbar Crocodile during her extra turn?
A: Yes. The phasing event happens during the untap step, so if that step is skipped, nothing phases in or out that turn. As such, Sandbar Crocodile will still be phased in when Amy takes her extra turn, so it can attack during that turn as normal.
Note: None of Amy’s phased out permanents will phase in during her extra turn either.
Q: Amy steals Nicole’s Grizzly Bears with Vedalken Shackles. Then Nicole uses Vision Charm to make Vedalken Shackles phase out. What happens?
A: Continuous effects with “for as long as” durations end when the appropriate permanent phases out because the game can no longer see it. In this case, that means that the Grizzly Bears will revert to Nicole’s control immediately since the game no longer sees Vedalken Shackles as being tapped.
Q: Amy attacks with Grizzly Bears equipped with a Vulshok Morningstar. Nicole blocks with a Hill Giant and uses Reality Ripple to phase out Vulshok Morningstar. What happens?
A: Hill Giant slays Grizzly Bears in combat because the latter no longer receives the buff from the equipment. During Amy’s next turn, Vulshok Morningstar phases in unattached to anything.
Note: If a permanent was attached to something and phases out directly, as is the case here, it will phase in attached to the same permanent if possible. If the permanent it was attached to is no longer on the battlefield, as here, it phases in unattached.
Q: Amy casts Dominate on Nicole’s Grizzly Bears. Then, Nicole enchants Grizzly Bears with Teferi’s Curse. What happens?
A: Because Grizzly Bears now has phasing, it will phase in and out during its controller’s untap step. This means that the phasing will happen during Amy’s turn. Because phasing in or out does not involve changing zones, this Grizzly Bears is considered the same object before and after it phases in or out. Accordingly, the effect of Dominate will still be applicable to it.
Note: “Phased out” and “phased in” are statuses that a permanent can have, just like “tapped” or “untapped.” The phasing event doesn’t change a permanent’s zone, just its status. Therefore, phasing does not affect whether Dominate’s effect continues to apply any more than tapping or untapping would.
Q: Amy controls an Ivory Tower and two Teferi’s Imps, one phased out and the other phased in. What happens as she begins her turn?
A: At the beginning of her untap step, one Teferi’s Imp will phase out and the other will phase in. Phasing out and phasing in happen as part of a single event, so these will happen simultaneously. This will cause the appropriate ability of each imp to trigger. These abilities are not put on the stack yet because no player gets priority during the untap step; it is only during Amy’s upkeep that this happens. During Amy’s upkeep, Ivory Tower will also trigger. Amy controls all three of these triggered abilities, so she chooses the order they are put onto the stack. She can choose any order she wants, even if that doesn’t correspond to the order they triggered. Amy can even stack the abilities so she draws first, then gains life, then discards.
Note: Astute readers may be wondering how Teferi’s Imp’s phase out ability functions. After all, the game checks after any game event to see if any triggered abilities exist that have triggered and need to go on the stack. Immediately after Teferi’s Imp phases out, that ability does not exist, so how does the game know it triggered? The answer is that for certain triggered abilities, the game “looks back in time” to before the trigger event happens to determine if they trigger. The most well-known example of this is zone-change triggers (including abilities that trigger when the permanent they’re on dies). Phase-out triggers are treated like this too for the same reason.
Q: Amy controls an Isochron Scepter imprinted with Boomerang. Nicole uses Vision Charm to phase Isochron Scepter out. What happens during Amy’s next turn?
A: When Isochron Scepter phases back in, it will still be the same object that it was when it phased out. It hasn’t changed zones, so it retains everything about its previous identity and Boomerang is still imprinted on it. Likewise, because phasing in doesn’t count as entering the battlefield, the imprint ability does not trigger and Amy does not get to imprint another card on it.
Q: Amy controls a Batterskull that’s equipped to a Germ token. Nicole enchants the Germ token with Teferi’s Curse. What happens?
A: During Amy’s next untap step, the Germ token will phase out. Batterskull and Teferi’s Curse will phase out indirectly at the same time because they’re attached to something that’s phasing out. Phasing out doesn’t cause the token to cease to exist the way changing zones would, so the Germ token will phase back in during Amy’s subsequent untap step. The Batterskull and Teferi’s Curse that phased out with it will phase back in still attached to the Germ.