Fateseal

Fateseal is a keyword action similar to scry. The only difference between them is that when you scry, you affect your own library, and when you fateseal, you affect an opponent's library. Fateseal was introduced in Future Sight, but was based on the mechanic of the Mirage card Sealed Fate.

From the ()

• The fateseal action doesn't have a target. You choose which opponent to affect as part of performing the action.