Blink Dog

An attacking or blocking creature that phases out is removed from combat.

Any continuous effects with a "for as long as" duration, such as that of Mind Flayer, ignore phased-out objects. If ignoring those objects causes the effect's conditions to no longer be met, the duration will expire.

Choices made for permanents as they entered the battlefield are remembered when they phase in.

If an opponent gains control of your Blink Dog, activates its Teleport ability, and the duration of the control-change effect expires before it phases in, Blink Dog phases in under your control as that opponent's next untap step begins. If they leave the game before their next untap step, Blink Dog phases in as the next untap step begins after their turn would have begun.