Fandaniel, Telophoroi Ascian

• WOTC Official Reminder Textofficial rules
  Surveil — Look at the top N cards of your library. Put any number of them into your graveyard and the rest on top of your library in any order.

• WWizards of the Coast2025-06-06
  Official Ruling
  While resolving Fandaniel's second ability, the next opponent in turn order chooses up to one nontoken creature to be sacrificed, then each other opponent in turn order does the same. Then each of the chosen creatures are sacrificed simultaneously. Finally, each opponent who didn't sacrifice a creature this way loses 2 life for each instant and sorcery card in your graveyard.
• WWizards of the Coast2025-06-06
  Official Ruling
  Fandaniel's first ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack.

Rulings via Scryfall