Sunken Palace

The copy is created on the stack, so it's not "cast" or "activated." Creating the copy won't cause abilities that trigger when a player casts a spell or activates an ability to trigger.

Resolving copies of permanent spells become tokens as they enter the battlefield. These tokens are not considered "created" when this happens.

The controller of a copy can't choose to pay any alternative or additional costs for the copy. However, effects based on any alternative or additional costs that were paid for the original spell are copied as though those same costs were paid for the copy.

The copy will have the same targets as the spell or ability it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. If the spell is a permanent spell with targets, such as an Aura, you may also choose a new target for that spell. The new targets must be legal. If, for any target, you can't choose a new legal target, then it remains unchanged (even if the current target is illegal).

If the spell or ability that's copied is modal (that is, it says "Choose one —" or the like), the copy will have the same mode or modes. You can't choose different ones.

If the spell or ability has damage divided as it was cast or activated, the division can't be changed (although the targets receiving that damage still can). The same is true of spells and abilities that distribute counters.

Activated abilities contain a colon. They're generally written "[Cost]: [Effect]." Some keyword abilities are activated abilities and will have a colon in their reminder text.

A copy is created even if the spell or ability that caused the delayed triggered ability to trigger has been countered by the time that delayed triggered ability resolves. The copy resolves before the original spell.

If the spell or ability that's copied has an X whose value was determined as it was cast or activated, the copy will have the same value of X.