Wasn't sure if this counts as "spooky" enough given the horror tag, but a quick check of your profile assures me that you'll like it anyway:
One of my favorite podcasts is "The Common Descent Podcast", which spends each episode discussing the evolution of a particular group of life. For the past several years they've done "Spook-E" speculative evolution episodes each October for Halloween, where they discuss how various movie and folklore monsters could have evolved. Good nerdy fun.