Jorn, God of Winter

You'll still pay all costs to cast a spell this way, including any additional costs. You may also pay alternative costs if any are available.

Even though you may play the card, it isn't in your hand, so you can't, for example, discard it or foretell it.

If an effect allows you to play a specific modal double-faced card, you may cast it as a spell or play it as a land, as determined by which face you choose to play. If an effect allows you to cast (rather than "play") a specific modal double-faced card, you can't play it as a land.