Brokkos, Apex of Forever

Mutate {2}{U/B}{G}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Trample
You may cast Brokkos, Apex of Forever from your graveyard using its mutate ability.

Magic Online Promos

Ikoria: Lair of Behemoths

Ikoria: Lair of Behemoths Promos

If another effect gives you permission to cast Brokkos from your graveyard, you may cast it for any cost associated with that permission.

If you cast Brokkos with the permission granted by its last ability, you must pay its mutate cost to cast it. You can’t choose to pay its mana cost or another alternative cost.

Casting Brokkos with the permission granted by its last ability doesn’t change when you can cast it.