Convention organizers occasionally ask their guests to produce a piece of art to help promote the show. You can see one such piece here and another here.
For the drawing below, I decided to draw Brii from Grimwood's Daughter (in a different outfit) along with Dr. Strange, Moon Knight and an oddball, cartoony character I'd been trying to turn into a series called "Mr. Lizard".
True story: The fellow who bought this original hated the "Mr. Lizard" drawing so much that he painted over it with white out.