Phantasmal Unicorn

Flying, prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Phantasmal Unicorn becomes the target of a spell or an ability, sacrifice it.
"It was here! I saw it just a second ago!"
"There is no such thing as Unicorns man, I keep telling you that."
"You gotta believe me! It was right there!"