Leona, the Unbreakable

Vigilance
Whenever another nontoken creature enters the battlefield under your control, bolster 1.
(Choose a creature with the least toughness or tied
with the least toughness among creatures you control
and put one +1/+1 counters on it.)
{w},{t}: Tap target creature.
{2}{u}: Draw a card.
{b}{b}: Discard a card, proliferate.