An online retailer has caused outrage after its decision to sell a Caitlyn Jenner Halloween costume. The fancy-dress outfit is based on the clothing and styling the star wore on the Vanity Fair magazine where she presented herself to the world in her new identity. Using a shot of a man wearing a wig, corset and sash, people have branded the costume, marketing and messaging as insensitive and discriminatory.   Fans of Caitlyn, who has gained momentous popularity since identifying as transgender, have fought back against Spirit Halloween for their decision to stock the costume, labelling them “disgusting” and “transphobic”. Defending their position, Lisa Barr, senior director of marking at Spirit Halloween said: "At Spirit Halloween, we create a wide range of costumes that are often based upon celebrities, public figures, heroes and superheroes. We feel that Caitlyn Jenner is all of the above and that she should be celebrated. The Caitlyn Jenner costume reflects just that." The outfit has since been stocked by two more online retailers - anytimeoutfit.com and wholesalehalloweencostumes.com - as men's costume options. A Change.org petition has since been launched asking for the costume to be discontinued. Petition organiser Addison Vincent wrote: "Do not turn Cailtyn Jenner into a costume. Your profit will only lead to greater transphobia and marginalization of an already at-risk community.” The petition has gained momentum, with one signer writing: "I'm signing because this costume mocks the validity of a transgender's identity, implying a man wearing a dress is the same as a person dressing to their comfort and identity." Another user who has signed the petition writes: “As a trans women who faces harassment everytime I go out the door the idea of giving transphobic jerks more tools for their bigotry is disgusting to me. Please listen to the marginalized community you're affecting and pull this product.” Jenner’s rep, Alan Nierob, has declined to comment at this time. Images via Anytimecostumes.com