Heidi's favorite holiday is right around the corner!
The 42-year-old model is known for going all out for her Halloween costumes, but despite several Instagram posts detailing the creation of her outfit for this year, we can't figure out what she's gonna be!
"It's almost time for my favorite holiday! Costume prep time with the team at @prorenfx Can't wait for Halloween," Heidi wrote on one picture, where she seemed to be transforming into... a cake martian?
"So yucky but so worth it in the end," she captioned a followup pic, which led us to believe she will be dressing up as a googpy mannequin.
But in a video where the America's Next Top Model host is clearly being transformed into a Blue Man Group mummy, Heidi wrote, "Thanks @prorenfx team for making my crazy costume idea a reality."
And our best guess for her final post is Slimeacorn, so all bets are off really.
For the record, this was Heidi's finished costume last year: a giant butterfly.
"I always like to surprise," Heidi told Us Weekly last year about why she keeps her costumes under wraps. "I don't like to tell people what I'm gonna do because people have a certain expectation of what it's gonna be like. I like to just show up and not tell anyone what it's gonna be."
Can you tell what Heidi is going for with this newest costume?
In less Halloween related matters, watch Heidi tell ET why she'll never get married again below!