Rulings

• 2005-02-01
  Horobi's Whisper can target a creature even if you don't control a Swamp, but the spell does nothing.
• 2013-06-07
  You reveal all cards you intend to splice at the same time. Each individual card can be spliced only once onto any one spell.
• 2013-06-07
  A card with a splice ability can't be spliced onto itself because the spell is on the stack (and not in your hand) when you reveal the cards you want to splice onto it.
• 2013-06-07
  You choose all targets for the spell after revealing cards you want to splice, including any targets required by the text of any of those cards. You may choose a different target for each instance of the word "target" on the resulting spell.
• 2013-06-07
  If all of the spell's targets are illegal when the spell tries to resolve, it will be countered and none of its effects will happen.