thats an amazing artwork.
I think the idea of killing all creatures is great as long as Gravitational Collapse quanta costs is kept high.
To counter killing all creatures, players can just dun send all creatures out in a rush.
Since Gravitational Collapse affects your creatures too,
i can see it doing well in a control deck, many creature killing spells
with little creatures or weapon to attack opponent.
Thank goodness for public domain NASA illustrations

50% would make it practically just
hate.
I see what you mean, but creatures with higher attack are generally favored more then ones with higher health. Thanks for your support for the card though, glad to have input on the design.
I'm fairly sure this has been suggested before, although I could be wrong. But this card essentially kills all creatures who's attack is equal to or greater than their HP, which essentially can completely wipe out several elements completely. As jonathan says, there are too few creatures that have more HP than attack, and most of them are in either earth of gravity. You could potentially tweak the card by reducing the damage dealt (such as make it 50% of the attack, for example) but raising the cost isn't a good fix.
Anyway, I hope you keep making cards around here
I assure you this isn't a copy or a repost; if you just a mean a card with the same effect, then I might have missed it, although I did try to check to make sure a card like this wasn't somewhere already.
Yeah, I can see it wiping out most elements. 50% of their attack being dealt as damage might work, as it still takes out the glass cannons easily without having as high a chance to wipe the enemy board, but I also feel like that makes the card a lot less... intuitive? That's definitely a possibility, though.
Thank you, I'll keep trying to think up new interesting cards!
Saying the effect is innately OP is like saying Maxwell's is OP
Long live the scarab swarm
Woah, I forgot completely about Maxwell's Demon. Your point makes sense, but also keep in mind Maxwell can't kill creatures with equal attack and health, which there are quite a few of. Also keep in mind it takes a while to Maxwell's their entire board. Still, you have a point, and that does make this card seem somewhat more possible, so thank you for the contribution! I really wish we could playtest cards like this, it's hard to judge it when nothing very close to its effect is in the game.