If you don’t have at least as many cards in your library as lands you control when Lasyd Prowler’s first ability resolves, you can’t choose to mill that many cards.
2025-04-04
The value of X is calculated only once, as Lasyd Prowler’s renew ability resolves.
2025-04-04
If a card with a renew ability is put into your graveyard during your turn, you can activate that ability if it’s legal to do so before any other player can take any actions.
When this creature enters, you may mill cards equal to the number of lands you control.
Renew — , Exile this card from your graveyard: Put X +1/+1 counters on target creature, where X is the number of land cards in your graveyard. Activate only as a sorcery.
, Exile this card from your graveyard: Put X +1/+1 counters on target creature, where X is the number of land cards in your graveyard. Activate only as a sorcery.