I just tried Claude Sonnet with the Pelican & Walrus setup, but asked it for something in style of Norm Macdonald's humor, which would seem a potentially good fit for this type of idea. It got the idea of a rambling story (cf Macdonald's moth joke) that mostly ignored them being a Pelican and Walrus, which seemed promising, but still failed to deliver. I'm guessing with some more guidance and iteration it could have come up with something.