Multicolor Personal Decoy This card actually seems immensely annoying for your opponent, and not just because of all the quacking
This free copy needs to be cast as a normal spell, and can be countered, but it's completely free each turn, even if previous free copies have been countered or disrupted
(7/23/2021) An effect that says "choose a target, then roll a d20" or similar still uses the normal process of putting an ability on the stack and resolving it
Nulldrifter has been the card I'm iffy about because I kept comparing it to Mulldrifter, but that's not really fair since they serve different purposes
While there wasnt a surplus of good X-spells to sink extra mana into, there were still plenty of occasions where youd want to drop Koth and -2 in order to make another big play in the same turn
No one, as far as I know, has ever gotten past one