You can’t choose to use a splice ability if you can’t make the required choices (targets, etc.) for that card’s rules text. You can’t splice any one card onto the same spell more than once. If you’re splicing more than one card onto a spell, reveal them all at once and choose the order in which their effects will happen. The effects of the main spell must happen first.
July 22, 2016 · Eldritch Moon
You choose which permanent to sacrifice as you make choices for the spell (see rule 601.2b), and you sacrifice that permanent as you pay the total cost (see rule 601.2h).
July 17, 2015 · Magic Origins
The permanent is sacrificed at the same time the spell is announced (see rule 601.2a). The total cost of the spell is reduced by the sacrificed permanent’s mana cost (see rule 601.2f).
February 1, 2014 · Born of the Gods
The permanent is sacrificed at the same time the spell is announced (see rule 601.2a). The total cost of the spell is reduced by the sacrificed permanent’s mana cost (see rule 601.2e).
July 13, 2013 · Magic 2014
The permanent is sacrificed at the same time the spell is announced (see rule 601.2a). The total cost of the spell is reduced by the sacrificed permanent's mana cost (see rule 601.2e).
September 30, 2011 · Innistrad
The card with ninjutsu remains revealed from the time the ability is announced until the ability leaves the stack.
June 17, 2011 · Commander 2011
The card with ninjutsu remains revealed from the time the ability is announced until the
April 1, 2011 · Duel Decks: Knights vs. Dragons
A player can't cast spells once a spell with epic he or she controls resolves, but effects (such as the epic ability itself) can still put copies of spells onto the stack.
February 4, 2011 · Mirrodin Besieged
A player can’t cast spells once a spell with epic he or she controls resolves, but effects (such as the epic ability itself) can still put copies of spells onto the stack.
October 1, 2010 · Scars of Mirrodin
A player can’t cast spells once a spell with epic he or she controls resolves, but effects
February 1, 2010 · Worldwake
A player can't cast spells once a spell with epic he or she controls resolves, but effects (such as the epic ability itself) can still put copies of spells onto the stack.