Abilities that change the power of a creature (such as the one of Collective Blessing) affect only creatures on the battlefield. They won’t change a creature spell’s power on the stack.
01-10-2012
wotc
Essence Backlash can target a creature spell that can’t be countered. If Essence Backlash resolves, it won’t counter the spell but it will still deal damage.
01-10-2012
wotc
If the creature’s power is * and it has an ability defining its power, use that ability to determine its power.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.