Halloween, mrs incredible costume horror fests and zombie walks are the perfect time for the gross zombie baby belly! 5 – Zombie Baby! I went with Lumpy Space Princess from Adventure Time. I tried the Maternity Fairy costume from a costume shop and I think most of these kind of costumes are really just plus size costumes repackaged. These are incredible works of art that took hours and hours of planning and constructing to pull off, and of course they look amazing.