Splice is a keyword ability.
Antony is casting an Ethereal Haze and has a Glacial Ray in hand. As he casts the Ethereal Haze, he may reveal Glacial Ray from his hand and pay . If he does this, he will be able to choose a target for Ethereal Haze and have it deal 2 damage to that creature when it resolves, in addition to preventing all damage.
- 702.46a. Splice is a static ability that functions while a card is in your hand. "Splice onto [subtype] [cost]" means "You may reveal this card from your hand as you cast a [subtype] spell. If you do, copy this card's text box onto that spell and pay [cost] as an additional cost to cast that spell." Paying a card's splice cost follows the rules for paying additional costs in rules 601.2b and 601.2e-g.
- 702.46b. You can't choose to use a splice ability if you can't make the required choices (targets, etc.) for that card's instructions. 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 instructions will be followed. The instructions on the main spell have to be followed first.
- 702.46c. The spell has the characteristics of the main spell, plus the text boxes of each of the spliced cards. The spell doesn't gain any other characteristics (name, mana cost, color, supertypes, card types, subtypes, etc.) of the spliced cards. Text copied onto the spell that refers to a card by name refers to the spell on the stack, not the card from which the text was copied.
- 702.46d. Choose targets for the added text normally (see rule 601.2c). Note that a spell with one or more targets will be countered if all of its targets are illegal on resolution.
- 702.46e. The spell loses any splice changes once it leaves the stack (for example, when it's countered, it's exiled, or it resolves).