Current design:25 nora Target champion takes 8 Magical damage and receives a hidden curse. Each time this spell is cast, that champion loses 2 life. Before buffs / nerfs:25 nora Target champion takes 8 Magical damage. The next time this spell is played, that champion takes 2 additional Magical damage.
Still a mostly useless spell imo. The damage is not really worth it and the additional damage is unlikely to ever be a factor. As a rule of thumb i do not cast a spell unless it has a potentially significant impact on the game in the long run or makes me ably to kill a champion. This spell will make me able to kill a champion for relatively cheap, but it is rare to get people to 8 or less hp and not have an aura or some other effect to finish the job and the added damage on recasts is very unlikely to ever happen or even be a deciding factor. Best case scenario is that you have 2 opposng champions with 10 and 8(or less) hp. Cast it first on the one with 10 and then on the one with 8 and both will die. But it will cost you 2 slots and 50 nora. Might as well do it with Anethema for 1 spell slot, or if they are close with Chainlightning or a third option.