Phasing is a keyword ability which causes permanents to "phase in" and "phase out". During each player's untap step, before the active player untaps, all phased-in permanents with phasing that player controls "phase out". At the same time, all phased-out permanents that phased out under that player's control "phase in". Spells and abilities can also cause permanents to phase in or out. When a permanent phases out, it is treated as thought it didn't exist; a phased-out permanent can't be affected by anything in the game that doesn't specifically mention phased-out permanents.
When a permanent phases out, it does not change zones or leave the battlefield, so no enters-the-battlefield or leaves-the-battlefield triggered abilities will trigger. Any Auras, Equipment, and/or Fortifications attached to that permanent phase out with it; this is called "phasing out indirectly". A permanent that phases in is treated by the game rules as the same object that phased out. As a result (and unlike a permanent that is flickered), it retains any counters that were on it, and, if it's a creature, it is unaffected by summoning sickness, so that it can attack and use activated abilities with the tap () or untap () symbols in their activation costs during the turn it phases back in. Auras, Equipment, and/or Fortifications attached to that permanent "phase in indirectly" when the permanent itself phases in.
All tournament-legal cards with phasing were printed during Mirage block.
From the Comprehensive Rules:
- 702.25. Phasing
- 702.25a Phasing is a static ability that modifies the rules of the untap step. During each player’s untap step, before the active player untaps his or her permanents, all phased-in permanents with phasing that player controls “phase out.” Simultaneously, all phased-out permanents that had phased out under that player’s control “phase in.”.
- 702.25b If a permanent phases out, its status changes to “phased out.” Except for rules and effects that specifically mention phased-out permanents, a phased-out permanent is treated as though it does not exist. It can’t affect or be affected by anything else in the game.
- Example: You control three creatures, one of which is phased out. You cast a spell that says “Draw a card for each creature you control.” You draw two cards.
- Example: You control a phased-out creature. You cast a spell that says “Destroy all creatures.” The phased-out creature is not destroyed.
- 702.25c If a permanent phases in, its status changes to “phased in.” The game once again treats it as though it exists.
- 702.25d The phasing event doesn’t actually cause a permanent to change zones or control, even though it’s treated as though it’s not on the battlefield and not under its controller’s control while it’s phased out. Zone-change triggers don’t trigger when a permanent phases in or out. Counters remain on a permanent while it’s phased out. Effects that check a phased-in permanent’s history won’t treat the phasing event as having caused the permanent to leave or enter the battlefield or its controller’s control.
- 702.25e Continuous effects that affect a phased-out permanent may expire while that permanent is phased out. If so, they will no longer affect that permanent once it’s phased in. In particular, effects with “for as long as” durations that track that permanent (see rule 611.2b) end when that permanent phases out because they can no longer see it.
- 702.25f When a permanent phases out, any Auras, Equipment, or Fortifications attached to that permanent phase out at the same time. This alternate way of phasing out is known as phasing out “indirectly.” An Aura, Equipment, or Fortification that phased out indirectly won’t phase in by itself, but instead phases in along with the permanent it’s attached to.
- 702.25g If an object would simultaneously phase out directly and indirectly, it just phases out indirectly.
- 702.25h An Aura, Equipment, or Fortification that phased out directly will phase in attached to the object or player it was attached to when it phased out, if that object is still in the same zone or that player is still in the game. If not, that Aura, Equipment, or Fortification phases in unattached. State-based actions apply as appropriate. (See rules 704.5n and 704.5p.)
- 702.25i Abilities that trigger when a permanent becomes attached or unattached from an object or player don’t trigger when that permanent phases in or out.
- 702.25j Phased-out permanents owned by a player who leaves the game also leave the game. This doesn’t trigger zone-change triggers. See rule 800.4.
- 702.25k Phased-out tokens cease to exist as a state-based action. See rule 704.5d.
- 702.25m If an effect causes a player to skip his or her untap step, the phasing event simply doesn’t occur that turn.
- 702.25n Multiple instances of phasing on the same permanent are redundant.
- Sandbar Crocodile -
Creature — Crocodile
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
 Color percentages
There is a total of 16 cards that involve phasing, which divide by color as such:
- Blue = 82 %
- Green = 6 %
- Land = 6 %
- Multicolor = 6 %
 See also
- Phased out - an obsolete game zone previously used to deal with phased-out permanents prior to the Magic 2010 rules
 Enchantments that grant Phasing