Escape

Escape is a keyword ability introduced in Theros Beyond Death, where it is connected to the Returned escaping from Nyx. Spells with escape can be cast from the graveyard for their escape cost. The cost includes exiling a number of other cards from the graveyard. If a creature escapes, it may receive an additional bonus.

Description
If a card with escape is in your graveyard, you can cast it. Escape provides you with an alternative cost with two components: an amount of mana you'll have to pay and a number of other cards you'll have to exile from your graveyard. Escape doesn't change when you can cast the spell. Instants with escape are good to go anytime you have priority; the other card types can be cast only during your main phase when the stack is empty.

Casting a spell using escape doesn't change any of the normal rules for casting a spell. The spell goes on the stack. It can be countered or otherwise responded to. Its converted mana cost doesn't change — it's always based on the mana cost, not the escape cost.

When an instant or sorcery spell with escape resolves (or is countered or otherwise leaves the stack), it returns to its owner's graveyard. Permanent spells with escape that resolve head to the battlefield, but if they die later, they'll head back to the graveyard. Cards can escape over and over again throughout the game as long as you have enough other cards to exile and mana to spare.

A few creature cards have abilities that say they escape with a number of +1/+1 counters. This just means that if you cast them from your graveyard using the escape mechanic, they'll enter the battlefield with that many +1/+1 counters.

Rulings

 * Escape's permission doesn't change when you may cast the spell from your graveyard.
 * To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as an escape cost), add any cost increases, then apply any cost reductions. The converted mana cost of the spell remains unchanged, no matter what the total cost to cast it was and no matter whether an alternative cost was paid.
 * 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.
 * If a card has multiple abilities giving you permission to cast it, such as two escape abilities or an escape ability and a flashback ability, you choose which one to apply. The others have no effect.
 * 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.
 * If a card with escape is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.
 * Once you begin casting a spell with escape, it immediately moves to the stack. Players can't take any other actions until you're done casting the spell.