Grolnok, the Omnivore
Legendary Creature — Frog
Whenever a Frog you control attacks, mill three cards.
Whenever a permanent card is put into your graveyard from your library, exile it with a croak counter on it.
You may play lands and cast spells from among cards you own in exile with croak counters on them.
DZO
Innistrad: Crimson Vow (VOW)
• #324Rulings
Grolnok's last ability allows you to play lands and cast spells from among all cards you own in exile with croak counters on them, regardless of whether they were put there by the Grolnok that's currently on the battlefield or by an earlier incarnation.
(wotc • 2021-11-19)
Grolnok, the Omnivore's second ability exiles all permanent cards that are put into your graveyard from your library, not just those that you mill when a Frog you control attacks.
(wotc • 2021-11-19)
Rulings
Grolnok's last ability allows you to play lands and cast spells from among all cards you own in exile with croak counters on them, regardless of whether they were put there by the Grolnok that's currently on the battlefield or by an earlier incarnation.
(wotc • 2021-11-19)
Grolnok, the Omnivore's second ability exiles all permanent cards that are put into your graveyard from your library, not just those that you mill when a Frog you control attacks.
(wotc • 2021-11-19)