Doctor Stable is THE most underrated MLP background character ever. Sure, his design is just a slight variation of Caramel, and even his cutie mark is pretty uninspired, but come on! He's got some of the best dialogue in the whole series, he balances kindness and cynism beautifully, and he's got a great supporting cast of nurses and patients!
And Screw Loose. I love this mare so much. Not only was her one scene hilarious, but it was actually pretty gutsy. Plus, just the way the character is presented makes you want to learn more about her. I'm so glad she made a cameo this last season, brief as it was, it was pretty sweet.
So what happens when you put them together? Well, awesome sauce drawings like this one
, which is what inspired this drawing.