Eidolon used his matter creation power.  As with the Faerie Queen’s monster of steel, this was derived from a single point, an expanding creation of matter.  In this case, however, it was an explosion.  Carbon unfolded from a single point.  Eidolon chose Scion’s right ear canal as the center point.

The carbon expanded as a sphere, and there was a glimmer of Scion’s reaction as the orb expanded until it was a hundred feet across.  A distortion, golden flesh stretching.

Blood?

Wildbow, Worm, 27.x