From chapter 38 of the Labyrinth fanfic "Dramatic Orchestrations". Sarah and Jareth, magically disguised as children, come across a gargoyle-esque statue in the sublevels of Castle Aryn, and the little imp seems to resemble Jareth to a certain degree.

"In front of them was… a wall. It was a very nice wall, all things considered, had probably taken the masons who built it years to lay down all that stonework. There was a slight recess in the center of it, where a wicked looking stone-imp jutted out from the torso up, one hand held out in supplication while the other stayed at his side hiding devilish claws. Its’ face was curved in an insane grin and blue light flared from the sapphire stones that made up its’ eyes. A mop of unruly hair, whose intricate detail had probably driven the stone carver mad, almost hid a pair of delicately pointed ears and nearly covered the tiny horns that spiraled around said ears."

Not exactly the way I pictured it, but rather close under the circumstances. Done in pencil on bristal and filled in with watercolor, which I apparently have little talent for. Try not to obsess over the little mistakes, it'll drive you batty. As usual, the original sketch turned out better.