Ob Nixilis, the Hate-Twisted
Legendary Planeswalker — Nixilis
Whenever an opponent draws a card, Ob Nixilis deals 1 damage to that player.
-2 : Destroy target creature. Its controller draws two cards.
Yongjae Choi
War of the Spark (WAR)
• #100Rulings
If the target creature is an illegal target by the time Ob Nixilis's last ability tries to resolve, the ability doesn't resolve. No player draws two cards. If the target is legal but not destroyed (most likely because it has indestructible), its controller does draw two cards.
(wotc • 2019-05-03)
If Ob Nixilis leaves the battlefield before his last ability resolves, most likely because he only had 2 loyalty when you activated the ability, his first ability won't exist to trigger when the creature's controller draws two cards.
(wotc • 2019-05-03)
Rulings
If the target creature is an illegal target by the time Ob Nixilis's last ability tries to resolve, the ability doesn't resolve. No player draws two cards. If the target is legal but not destroyed (most likely because it has indestructible), its controller does draw two cards.
(wotc • 2019-05-03)
If Ob Nixilis leaves the battlefield before his last ability resolves, most likely because he only had 2 loyalty when you activated the ability, his first ability won't exist to trigger when the creature's controller draws two cards.
(wotc • 2019-05-03)