Grifone di Brumaconca

Misthollow Griffin can also be cast from a player's hand.

Misthollow Griffin doesn't have an ability that exiles itself. Some other effect will be needed to get the card into exile.

Misthollow Griffin's ability doesn't change when you can cast creature spells: when you have priority during your main phase when the stack is empty.

You must still pay Misthollow Griffin's mana cost when you cast it from exile.