Instant Kicker {W} (You may pay an additional {W} as you play this spell.) Target player can't play spells this turn. If the kicker cost was paid, creatures can't attack this turn.1
This spell does nothing to spells that have already been announced prior to it resolving or to creatures which are already attacking. [Planeshift FAQ 2001/01/26] In other words, this spell does not counter another spell and does not remove attacking creatures from an attack. [D'Angelo 2001/02/18]
The player may announce spells in response to this spell. This spell does not have any effect until it resolves. [D'Angelo 2001/03/12]
This spell does not affect the abilities of permanents. It only affects spells. [DeLaney 2001/02/12]
This spell makes it so the player cannot declare any creatures as attackers this turn. [Barclay 2001/04/05] The card's wording may be updated in the near future to make this clear. Other cards may receive a similar ruling. [D'Angelo 2001/04/16]
Planeshift
(Rare)