Ghroth, the harbinger

When Ghroth, the harbinger enters your
hand, you must play him immediately. Bring
one random ancient elder god into play, shuffle Ghroth, the harbinger into your library.
He floats through the cosmos, devoid of purpose, singing the song of spheres. Hearing his song, the great old ones on those worlds he passes awake.
Much to the misfortune of the inhabitants.