If you're looking for a costume idea, here are some of the best! ... If you want to make your own, the original website has design specifications

Alien creature from John Carpenter's The Thing...

This gruesome shape-shifting alien creature was featured in John Carpenter's 1982 remake of The Thing.

The Thing alien creature special effect display
John Carpenter's The Thing alien creature
The Thing creature modelRob Bottin's The Thing creature effects
When a parasitic alien life-form infiltrates an American Antarctic research station it kills and assimilates other organisms. At one stage it it takes over the form of 'Vance Norris' (played by Charles Hallahan) and in an attempt to escape being burned alive, it separates his head from the rest of the body and sprouts crablike legs, amongst other things.

The Thing movie poster
John Carpenter's The Thing movie poster
Rob Bottin was make-up effects creator and designer on the classic sci-fi horror, and responsible for creating the outlandish and over-the-top special effects that are still impressive today.
The Thing alien head
The Thing craeture movie propThe Thing alien creature effect
Rob Bottin The Thing creature
I'm not sure whether this is an original concept model, a prop used in the production of the movie or a reproduction for use in Universal Orlando's Horror Make-Up Show (where it was photographed on September 23, 2010), but regardless it's still an eye-catching creature design.

Buy the movie: The Thing [Blu-ray]