Captivating Unicorn

Creature - Unicorn

Constellation — Whenever an enchantment enters the battlefield under your control, tap target creature an opponent controls.

"Gazing at the unicorn, I felt closer to the majesty of Nyx than I ever had before."
—Oineus, traveling merchant

4/4

2020-01-24 A constellation ability triggers whenever an enchantment enters the battlefield under your control for any reason. Enchantments with other card types, such as enchantment creatures, will also cause constellation abilities to trigger.
2020-01-24 An Aura spell that has an illegal target when it tries to resolve doesn't resolve and is instead put into its owner's graveyard. It doesn't enter the battlefield, so constellation abilities don't trigger.

Card is in preconstructed decks:

mtg.wtf