The next creature card you play this turn can be played as though it had flash.
Draw a card.
5/1/2007 Scout’s Warning works just like Quicken, except for creatures instead of sorceries.
5/1/2007 Scout’s Warning affects only the next creature card cast that turn, even if that creature already had flash.
5/1/2007 Scout’s Warning allows you to cast a noncreature card with morph (such as Lumithread Field) face down as though it had flash. It won’t affect that card if you cast it face up.
4/15/2013 You don’t choose a creature card when Scout’s Warning resolves. Rather, this sets up a rule that is true for you until the turn ends or until you cast a creature card, even if you cast that creature at a time you normally could.
4/15/2013 If you cast multiple Scout’s Warnings on the same turn, they’ll all apply to the very next creature spell you cast.
4/15/2013 After Scout’s Warning resolves, you can suspend a creature card in your hand any time you can cast an instant. As soon as you actually cast a creature card, you lose this capability.
4/15/2013 You cannot use this effect to play Dryad Arbor during an opponent’s turn.