Dr. Yekyll's Laboratory if you are really lucky. It was also Referral System & Facebook contest prize. You could catch this costume if it is put up for auction by the Halloween Alien. It's a restricted costume meaning that you can't just get it through traditional means. Putting this costume on a marapet will make it turn into a mutant! All mutant pets are taupe and red with deformities like extra tails, limbs, etc. Old mutant pets have yellow eyes with bags under them and their brains sticking out. Modern Mutant pets have red horns, spots, stripes, and claws.