­Reviving Vapors + Sudden Impact

Nice. I like it.

Ouch. Very very swingy.

Wow. Um. Looks like an incredibly potent finisher for an aggro deck, though those aren't normally blue-red. This is best friends with Goblin Guide because it lets you know when to fire this off for the most damage.

My initial instinct is that it's very strong, too; but it's also quite unpredictable. Sometimes it'll brain your opponent for 12 damage and end the game; sometimes it'll dig them past three lands and the resulting mana flood.

I could up the mana cost to discourage this from being played competitively.

But note that it's unreliable, and if you do fail to kill your opponent, you've given them such a massive advantage you probably won't recover.

I'd say 'up the mana cost to discourage this from being played competitively'. Most Spikes hate this sort of effect for that exact reason. They'll feel trapped. They have to play this card because, on average, it will deal four damage or more to the opponent, making it a good card. But they hate playing with it, because winning with it came down to being lucky, not by skill on their part. You can make your own luck with this card... but it's not even consistent with decks that do.

If I was to guess, I'd say the type of player who would like this card the most would be the type of player who would be optomistic with this card. They'd expect to get a three a four and a land... about seven damage... and would hope to get really lucky and hit for a lot more. I think you can cost this based on their optimistic desires.

I definitely like it, but I think the problem is the swingyness, not the power level, in that if it's cheap, Spike feels obliged to play it and doesn't like it, and if it's expensive, Timmy doesn't like it because it may fizzle out for 0 damage.

Making it less swingy would make it less interesting though, I wonder if there's any better way of keeping the idea but making it more printable?

Make a symmetrical version? Make a version that goes off for one card every turn? Make it a death trigger so you can hope for the best, but not be able to control exactly when it goes off? Give it some filtering properties (eg. "reveal cards from the top of your library until you reveal one/two/three nonland cards")?

I don't know... there's a sub-section of Timmy that likes coin flipping. Timmy doesn't like it when he gets 0 on a spell like this... but if he never could get 0, getting 10 damage wouldn't be such a victory. I think he likes the card despite himself.

Good point, the "wow, I flipped up BOTH of his progenitii" Timmy will like this.

I also think the "Ok, how can I copy this 10 times or so?" guy will like it.

There's definitely a lot of players who would love this card.

As for Spikes, I think you're overrating this card. If you think of it as a 4-5 damage spell, that's cool. You can make a burn deck out of that. However, it is not. Unless you're dealing the last 4-5 damage, if you use this, you'll give an incredible advantage to your opponent, and even more situations where he/she can draw his lifelink sideboarded creature or whatever. The rest of the time, it's a card that sits in your hand and does nothing. Even if you try to play these at the last moment (so that your opponent probably never uses the drawn cards), it's three mana per spell, which is a lot for a deck that supposedly wants to win fast. Finally, blue is not the most aggro colors, and if it is, it often wants tempo-oriented cheap burn spells that can hit creatures, not this. So it's not like it's a very good card as it is.