Heidi Klum is notorious for going all out on Halloween, and it looks like this year will be no exception. While she's not telling the world what she's going to be just yet, the model did share some behind-the-scenes pics from her costume fitting on Instagram this week. Though, "fitting" may not be quite the right word for what this year's costume entails. Sneak-peek shots show Klum being covered in goo at a prosthetics studio, followed by People's exclusive pictures of what appear to be a very ample latex derriere and bosom. Add to that the fact that Klum tapped former Project Runway designer Christian Siriano to create the fabric portion of her Halloween ensemble, and we're starting to get an idea of what — and who — Klum is channeling. “This year’s costume is sort of a male’s fantasy," she shared with People. "That’s all I’m going to say!”Anyone else want to bet that she's going as Kim Kardashian? Or maybe Khloé? We'd know those buns anywhere.