Covetous Castaway

“Disturb [cost]” means “You may cast this card transformed from your graveyard by paying [cost] rather than its mana cost.”

If you copy a permanent spell cast this way (perhaps with a card like Double Major), the copy becomes a token that's a copy of the card's back face, even though it isn't itself a double-faced card.

When you cast a spell using a card's disturb ability, the card is put onto the stack with its back face up. The resulting spell has all the characteristics of that face.