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.)
Choose target card in a graveyard other than a basic land card.
SearchTo search for a card in a zone, look at all cards in that zone (even if it’s a hidden zone) and find a card that matches the given description.
If a player is searching a hidden zone for cards with a stated quality, such as a card with a certain card type or color, that player isn’t required to find some or all of those cards even if they’re present in that zone.
If a player is instructed to search a hidden zone for cards that match an undefined quality, that player may still search that zone but can’t find any cards.
If a player is searching a hidden zone simply for a quantity of cards, such as “a card” or “three cards,” that player must find that many cards (or as many as possible, if the zone doesn’t contain enough cards).
If the effect that contains the search instruction doesn’t also contain instructions to reveal the found card(s), then they’re not revealed.
If searching a zone is replaced with searching a portion of that zone, any other instructions that refer to searching the zone still apply. Any abilities that trigger on a library being searched will trigger.
If an effect offers a player a choice to search a zone and take additional actions with the cards found, that player may choose to search even if the additional actions are illegal or impossible.
An effect may instruct a player to search a library for one or more cards more than once before instructing a player to shuffle that library. This is the same as a single instruction for that player to search that library for all those cards. The player searches that library only once.
If multiple players search at once, each of those players looks at the appropriate cards at the same time, then those players decide in APNAP order (see rule 101.4) which card to find.
If an effect instructs a player to search outside the game for a card, that player may choose an appropriate card they own from outside the game. (CR 701.23) its owner's graveyard, hand, and library for all cards with the same name as that card and
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) them. Then that player shuffles.