Phasing

Phasing is a keyword ability that causes permanents to "phase in" and "phase out".

Description
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 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 though 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 in or 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, Equipments, 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 (undefined) 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.

History
Phasing inspired the design of the Flicker-ability. R&D didn't consider Phasing a well-understood mechanic, but used it nonetheless to clean up a few Oracle wordings early on. These were later reverted. ).

For a long time, the only tournament-legal cards with phasing had been printed during Mirage block. Its only reappearance was as an example of an outdated mechanic in Unhinged 's Old Fogey.

Change to keyword action
Thirteen years later it made a surprise return as an one-off on Commander 2017's Teferi's Protection. This featured a new reminder text: (When permanents are phased out, they're treated as if they don't exist. They phase in before you untap during your untap step.) As of Commander 2017, tokens which phase out phase back in the same as nontoken permanents, instead of ceasing to exist as a state-based action.

As of 2020, R&D is considering to give phasing deciduous status as a keyword action ("phase out"), because it allows for different design space than flickering, e.g Auras and Equipment don't "fall off" of and "enters the battlefield" and "leaves the battlefield" effects don't work. They are not interested in the permanent keyword phasing where an object continually phases in and out every turn. Two Teferi cards in Core Set 2021 made use of the technology (Teferi, Master of Time and Teferi, Timeless Voyager) These featured the following reminder text (Treat it and anything attached to it as though they don’t exist until its controller’s next turn). It also made the return of in Double Masters possible.

Enchantments that grant Phasing

 * Cloak of Invisibility (creature)
 * Teferi's Curse (artifact or creature)
 * Shimmer (lands of the chosen type)
 * Vanishing (creature)
 * Oubliette</c>