Dark Evocation

You touch one willing or unwilling creature. Once before the spell ends, if the target is willing, they can roll a d6 and add the number rolled to one ability check of its choice and take a 1d4 of darkness damage. If the target is unwilling, they roll a d6 and subtract the number rolled to one ability check of your choice and you take a 1d4 of darkness damage.

It can roll the die before or after making the ability check. The spell then ends.