If you cast an omen card as an Omen, use only its alternative characteristics to determine whether it’s legal to cast that spell. For example, if you control Thundermane Dragon (“You may cast creature spells with power 4 or greater from the top of your library.”) and Twinmaw Stormbrood is on top of your library, you can cast Twinmaw Stormbrood, but not Charring Bite.
Scavenger Regent // Exude Toxin
If an Omen spell is copied, that copy is also an Omen and is shuffled into its owner’s library as it resolves. Its owner still shuffles their library, but the copy ceases to exist as a state-based action.
If a spell is cast as an Omen, its controller shuffles it into its owner’s library instead of putting it into its owner’s graveyard as it resolves.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. John Tedrick
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
