It was time for an evil undead magical pony transformation sequence! Equal parts this and this.

The spine settled all along Luminark's back, running up his neck and vanishing under his headdress. The ribs lanced down around his barrel one by one. Spikes of bone emerged from his tail and long jagged talons settled on the base of his hooves. And his eyes turned into bat slits too why not.

Then came two minutes forty seconds of posing and preening.

Only then did Luminark quietly acknowledge that he had disrupted the Archmage's important schedule. His job was to make her life more convenient and he had just done the opposite.

So he glanced one more time in the mirror, took on the slightly spooked aspect of a pony on a mission, and started to walk back the way he had come.