Creature â Cephalid
Threshold â€” As long as seven or more cards are in your graveyard, Cephalid Sage has "When Cephalid Sage enters the battlefield, draw three cards, then discard two cards."2/3
You draw three cards and discard two cards all while Cephalid Sageâ€™s ability is resolving. Nothing can happen between the two, and no player may choose to take actions.
If you donâ€™t have enough cards in your graveyard at the moment Cephalid Sage enters the battlefield, its threshold ability wonâ€™t trigger. If the number of cards in your graveyard changes and Cephalid Sage loses the ability once it has triggered, the ability will still resolve.