As an additional cost to
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) this spell, choose a creature you control or a warped creature card you own in
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13).
Close Encounter deals damage equal to the power of the chosen creature or card to target creature.