Callous Dismissal

2019-05-03 Army is a new creature type. It's possible to control a nontoken Army (perhaps a creature with the changeling ability) and, through combinations of other cards, it's possible to control multiple Army tokens. When instructed to amass, you may put +1/+1 counters on any of your Army creatures, and you may choose a different one each time.
2019-05-03 If you don't control an Army, the Zombie Army token that you create enters the battlefield as a 0/0 creature. Any abilities that trigger when a creature with a certain power enters the battlefield, such as that of Mentor of the Meek, will see the token enter as a 0/0 creature before it gets +1/+1 counters.
2019-05-03 Some spells that amass may require targets. If each target chosen is an illegal target as that spell tries to resolve, it doesn't resolve. You won't amass.

Card is in preconstructed decks:

mtg.wtf