Professor Onyx [Strixhaven: School of Mages Prerelease Promos] Nationals Promos Set: Kaladesh Inventions Type: Artifact

Set: Kaladesh Inventions Type: Artifact Rarity: Mythic Cost: {0} {T}

Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target

But where is the source

return target Spirit permanent card from your graveyard to the battlefield

When Oathkeeper

Professor Onyx [Strixhaven: School of Mages Prerelease Promos] Nationals Promos Set: Kaladesh Inventions Type: ArtifactSet: Strixhaven: School of Mages Prerelease Promos Type: Legendary Planeswalker Liliana Rarity: Mythic Cost: {4}{B}{B} Magecraft Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life. +1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard. 3: Each opponent sacrifices a creature with the greatest power among creatures that player