Okay, here's a thing. We're not qualified card designers by any means, but we reckon it wouldn't work mainly because of how OP the card is compared to the other card that converts creatures into damage -
Catapult One of the things that bug us is damage output. In Catapult's case we have a card that can deal about 50 damage in one attack, however it requires a quite ridiculous combo of Catapult, Titan, Freezing spell and Animate Weapon spell. You'd have to play that combo twice in order to defeat your opponent in a single turn, not to mention that it's easily counterable by Quintessence, Reverse Time and literally anything that has to do with permanent control. (It's also worth mentioning that this combo is actually quite expensive quanta-wise)
Here, however, we have something different - you'd only need a three card combo in order to win - Voodoo doll, Basilisk Blood and your Kamikaze, all of which can be powered by a single Supernova. Not only that, but it's also quite possible on getting all four cards in first turn. And while the "this card doesn't work on decks with Gravity/Darkness Mark" it's actually more likely that the card will end up in a rainbow deck with entropy mark or something.
Another thing that bugs us is that there's not potential counter to this. Catapult is easily destroyable or stealable, one BOOM and and there's no strategy left. Here we have a spell that turns a creature in, we take it, an unblockable damage, which really isn't great balance-wise.
I'd suggest rethinking the way the calculation works. Tripled unblockable damage doesn't sound good in any sort of scenario (See: Diving creatures + Shards of Freedom). Maybe something around 150% of HP would sound nicer