2019-07-12 : If either target is an illegal target as Vivien’s second ability tries to resolve, the creature you control won’t deal damage.

2019-07-12 : If one of the two target creatures becomes an illegal target in response to Vivien’s first ability, the +1/+1 counter that would have been put on that creature is lost. It can’t be put on the legal target.

2019-07-12 : In a casual game, a card you choose from outside the game comes from your personal collection. In a tournament event, a card you choose from outside the game must come from your sideboard. You may look at your sideboard at any time.

2019-07-12 : You can activate Vivien’s first ability without choosing any target creatures. The counters won’t be put on anything. This is a change from previous rules regarding distributing counters.

2019-07-12 : You choose how the counters will be distributed as you activate Vivien’s first ability. Each target creature must be assigned at least one counter. This means that you can’t put two counters on one creature but give two creatures trample.