I was poking around on the Simpsons Wiki site, and I found these images, which I have crudely assembled into one pic. I am not familiar with the episode, but it looks likes Lisa Simpsons subconscious personified.
Apparently young girls are inhabited by such things. Pixar’s next feature, “Inside Out” is about what goes on inside a girls mind. Below is a recently released image.
I’m not surprised that Pixar doesn’t include a chained up libido.