Elliot, Virtuous Ally

Vigilance, Lifelink

Whenever you gain life, untap target creature, then draw a card.

At the beginning of your end step, if you didn't attack this turn, put a +1/+1 counter on Elliot, then
if Elliot's power is greater than 9, gain control of target creature.

{7}{w}{w}{w}: Target player loses the game if they control no creatures.