Mountainside Troop

Whenever another human enters the
battlefield, you may add it to your party. (If a creature in your party would die, instead, remove that creature from your party and put a -1/-1 counter on
it.)
For each creature in your party, each other
creature in your party gets a +1/+1.
As you cast Mountainside Troop, create a party
and then put Mountainside Troop into that party.