The Snow-Thing was a Thing composed of several assimilated dogs which survived the kennel attack at U.S. Outpost 31. While planned for inclusion in the 1982 film The Thing, the creature was dropped due to financial and time constraints. It can be found in production artwork, the film script and novel.
Following the Kennel-Thing attack, the film script had the remaining sled dogs assimilated by pieces of the Thing which they had bitten off during the kennel fight, rather than be killed by Blair. They subsequently escape from the kennel and start high-tailing it to the Antarctic coastline. Upon discovering the dogs are missing, MacReady, Childs, and Bennings take off after them on snowmobiles.
This scene turns out to be one of three possible deaths for Bennings: his death we see in the film, getting murdered in the kennel, and this scene on the ice field that was never filmed. Here, Bennings gets pulled to his doom underneath the ice by one of the Dog Beasts. Although dropped from the film, the creature was featured in Alan Dean Foster's novelization of the film, which was heavily influenced by Lancaster's second draft of the screenplay.