Unknown Event

Sorcery

Destroy target creature or planeswalker. If today's date is May 6th, scry 1. If today's date is May 7th, fateseal 1. (To fateseal 1, look at the top card of an opponent's library. You may put that card on the bottom of their library.)

May of the Machine

The List

Instant

Put target creature on top of its owner's library, then fateseal 2. (To fateseal 2, look at the top two cards of an opponent's library, then put any number of them on the bottom of that player's library and the rest on top in any order.)

Spin into Myth

Secret Lair Drop

Creature — Sliver

All Slivers have "When this permanent enters, you may fateseal 1." (To fateseal 1, its controller looks at the top card of an opponent's library, then they may put that card on the bottom of that library.)