If you're going to draw a singin door, you have to decide what song the door is singing. I decided a song by The Doors would be appropriate.
Obnoxious Rhinoceros
Back in the '90s, when I couldn't think of something to draw, my friend Rob would randomly open the dictionary, blindly place his finger on the page, and call out the closest adjective. He'd repeat the process for a noun, and I would draw the result. "Obnoxious Rhinoceros" was the first combination I drew. For new illustrations, I prefer email suggestions, but often settle for a random word generator.