Split secondSplit second is a static ability that functions only while the spell with split second is on the stack. “Split second” means “As long as this spell is on the stack, players can’t cast other spells or activate abilities that aren’t mana abilities.”
Players may activate mana abilities and take special actions while a spell with split second is on the stack. Triggered abilities trigger and are put on the stack as normal while a spell with split second is on the stack.
Multiple instances of split second on the same spell are redundant. (CR 702.61) (As long as this spell is on the stack, players can't
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) spells or
activateTo activate an activated ability is to put it onto the stack and pay its costs, so that it will eventually resolve and have its effect. Only an object’s controller (or its owner, if it doesn’t have a controller) can activate its activated ability unless the object specifically says otherwise. A player may activate an ability if they have priority. See rule 602, “Activating Activated Abilities.” (CR 701.2) abilities that aren't mana abilities.)
EnchantEnchant is a static ability, written “Enchant [object or player].” The enchant ability restricts what an Aura spell can target and what an Aura can enchant.
For more information about Auras, see rule 303, “Enchantments.”
If an Aura has multiple instances of enchant, all of them apply. The Aura’s target must follow the restrictions from all the instances of enchant. The Aura can enchant only objects or players that match all of its enchant abilities.
Auras that can enchant a player can target and be attached to players. Such Auras can’t target permanents and can’t be attached to permanents. (CR 702.5) permanent
You control enchanted permanent.