I listen to a lot of podcasts while I'm chained to my drawing desk, and one of my favourites is The JV Club
(hosted by Janet Varney, or you may know her other name, Korra!) and 2 episodes ago, in which she interviewed Sex Nerd Sandra, a comment was made about Sandra riding a Koalasaur and how quickly a fan would draw it for them.
Someone else beat me to it on the show's Pinterest page
, but I am still that fan. The whole thing maybe took between 3 - 4 hours, working on it in bits and pieces over a few days - and is probably the most layered file I've worked on in photoshop for a long time.