Nightmare Incursion
Sorcery
Search target player's library for up to X cards, where X is the number of Swamps you control, and exile them. Then that player shuffles.
Legalities
- brawl: banned
- commander: legal
- legacy: legal
- modern: legal
- pauper: legal
- pioneer: banned
- standard: banned
- vintage: legal
Rulings
- 2008-08-01:
The cards are exiled face up, so everyone can see what they are. (This is true of every effect that exiles cards, unless the effect specifically says it exiles those cards face down.)