Dirgur Island Dragon

Casting a card as an Omen isn’t casting it for an alternative cost. Effects that allow you to cast a spell for an alternative cost or without paying its mana cost may allow you to apply those to the Omen.

If an effect instructs you to choose a card name, you may choose the alternative Omen name. Consider only the alternative characteristics to determine whether that is an appropriate name to choose.

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.