No one ever asked what was in Dina's concoctions, so long as they worked.

Deadly Brew

Each player sacrifices a creature or planeswalker of their choice. If you sacrificed a permanent this way, you may return another permanent card from your graveyard to your hand.

Foundations

Strixhaven: School of Mages

You cannot return the same permanent card that you sacrificed.

You choose which permanent card you're returning to your hand, if any, as Deadly Brew resolves, after permanents are sacrificed.

First the active player chooses which creature or planeswalker they'll sacrifice, then each other player in turn order does the same, knowing choices made before their choice. Then all those permanents are sacrificed simultaneously.

If you cast Deadly Brew and control any creatures or planeswalkers as it resolves, you must sacrifice one of them.