Fear of change, Uncommon, 9g
Players receive damage based on rarity of New cards in their hands
(C-4 U-8 R-12)
I hope that this only works for the one New card with highest rarity in each hand, though the more I look at it, the more I doubt that. Cards that discard/replace one's entire hand are going to make this an insanely OP juggernaut.
Scepter of evolution, for one example, would always cause this to deal 52 damage.
Whirlwind doesn't replace the hand but would result in at least 32 damage every time. But its cost and rarity make me think it should be capable of more than 12 damage at best, and its name has me thinking that it is intended to look at the sum of all New cards...
If it is only supposed to happen for one card, adding the word "highest" before "rarity" should make it clear. If it is meant to look at all cards, add "all" before "New" and maybe add a damage cap? Granted, the full cost is 9 gems AND some damage to yourself, but this seems far too easy to deploy as a finisher at such low cost.