Aeonus, the Northern Light

Lifelink, Trample, Vigilance
Other Unicorn creatures you own in any zone are Enchantment Creatures and get +1/+1.
Whenever a nontoken Enchantment enters the battlefield under your control, create a 2/2 white unicorn enchantment creature token with lifelink.
{10}{w}{g}, Tap twenty Unicorn creatures you control: You gain 100 life. Use this ability only once per game, it can't be countered.