How to find a Sea Unicorn

Creatures you control get +1/+1 .
{1}{w}{w}, {t}: Destroy target creature that
dealt damage to you this turn.
"In the depths of the ocean, where sunlight rarely
reached and the world was cloaked in mystery,
there lived a legend among the creatures of the deep.
It was the tale of the Pearlicorn, a tiny unicorn
that could be found nestled within the heart of shells,
just like precious pearls."