so if a spell has all of its targets become invalid then the spell fizzles upon attempted resolution.
What about some targets?
Spell has partial resolution right?
Say someone {Arc Lightning} And one of the targets gains hexproof in response. The rest still get zapped yes?
I cite {Hex} For the thought,
10/1/2005 You must target six different creatures. If you can't, you can't cast Hex. If some of the creatures become illegal targets before the spell resolves, Hex will still destroy the rest of them.
so a spell always tries to resolve as much as it can. however, if you dont have enough legal targets when casting the spell you cant legally cast it. thats why the ruling for {hex} makes sense. if you have 6 legal targets, you can cast hex. if in response, someone bounces 5 of the 6 creatures to their owners hands, {hex} will still do as much as it can and kill one. if you cast {arc lightning} and deal 1 to me and 2 to my {viscera seer}, i can sacrifice my {viscera seer} in my response but that wont counter your spell. ill still take the 1 damage.
heres an important ruling from the card {electrolyze} :
2/1/2006 If all chosen targets are illegal as Electrolyze tries to resolve, it will be countered and none of its effects will happen. No damage will be dealt and you won't draw a card.
but, if one of the targets is legal, and the rest are illegal upon resolution, you will still draw a card.