Elspeth, Sun's Nemesis

After an escaped spell resolves, it returns to its owner's graveyard if it's not a permanent spell. If it is a permanent spell, it enters the battlefield and will return to its owner's graveyard if it dies later. Perhaps it will escape again—good underworld security is so hard to come by these days.

If you activate a loyalty ability of Elspeth, she's put into your graveyard, and she escapes all in the same turn, she'll be a new permanent. You can activate one of her loyalty abilities even though she's represented by the same card.

If you cast a spell with its escape permission, you can't choose to apply any other alternative costs or to cast it without paying its mana cost. If it has any additional costs, you must pay those.