Eradicator Valkyrie

Flying, lifelink, hexproof from planeswalkers
Boast — {1}{B}, Sacrifice a creature: Each opponent sacrifices a creature or planeswalker. (Activate only if this creature attacked this turn and only once each turn.)

Magic Online Promos

Kaldheim Promos

Kaldheim

As the boast ability resolves, first the next opponent in turn order chooses a creature or planeswalker they control. Then each other opponent in turn order chooses a creature or planeswalker they control, knowing the choices made before their choice. Then all chosen creatures and planeswalkers are sacrificed at the same time.

Eradicator Valkyrie can’t be the target of abilities whose source is a planeswalker an opponent controls.