Lasyd Prowler
Creature — Snake Ranger
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.
Anna Pavleeva
Rulings
The value of X is calculated only once, as Lasyd Prowler’s renew ability resolves.
(wotc • 2025-04-04)
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.
(wotc • 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.
(wotc • 2025-04-04)
Rulings
The value of X is calculated only once, as Lasyd Prowler’s renew ability resolves.
(wotc • 2025-04-04)
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.
(wotc • 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.
(wotc • 2025-04-04)