Sea Gate Stormcaller

For spells with {X} in their mana costs, use the value chosen for X to determine the spell's mana value. If it's copied, the copy has the same value of X.

Sea Gate Stormcaller's delayed triggered ability will copy any instant or sorcery spell, not just one with targets.

You can't choose to pay any additional costs for the copy. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too. Notably, if the spell you copy was kicked, the copy or copies will also be kicked.