Kaya, Ghost Assassin
Legendary Planeswalker — Kaya
0
: Exile Kaya or up to one target creature. Return that card to the battlefield under its owner's control at the beginning of your next upkeep. You lose 2 life.
-1
: Each opponent loses 2 life and you gain 2 life.
-2 : Each opponent discards a card and you draw a card.
Chris Rallis
Treasure Chest (PZ2)
• #67Rulings
As the last ability resolves, each opponent will choose a card to discard and set it aside. Then all those cards are revealed and discarded simultaneously.
(wotc • 2016-08-23)
You choose whether or not to target a creature as you activate the first ability. If you chose a target creature, you choose whether to exile Kaya or that creature as the ability resolves. If you chose a creature and that creature is no longer a legal target as the ability tries to resolve, the ability doesn't resolve and none of its effects happen. You won't exile Kaya or lose 2 life.
(wotc • 2016-08-23)
If you didn't choose a target creature for the first ability, and Kaya isn't on the battlefield as the ability resolves, you'll just lose 2 life. No card will be exiled or returned to the battlefield.
(wotc • 2016-08-23)
Rulings
As the last ability resolves, each opponent will choose a card to discard and set it aside. Then all those cards are revealed and discarded simultaneously.
(wotc • 2016-08-23)
You choose whether or not to target a creature as you activate the first ability. If you chose a target creature, you choose whether to exile Kaya or that creature as the ability resolves. If you chose a creature and that creature is no longer a legal target as the ability tries to resolve, the ability doesn't resolve and none of its effects happen. You won't exile Kaya or lose 2 life.
(wotc • 2016-08-23)
If you didn't choose a target creature for the first ability, and Kaya isn't on the battlefield as the ability resolves, you'll just lose 2 life. No card will be exiled or returned to the battlefield.
(wotc • 2016-08-23)