Physical Description and Attributes
The Snowman's appearance most likely resembles a typical snowman built with real snow. However, it appears this one in particular has been given life, and is able to now interact with the physical world. In addition, this Snowman must be hostile to humans in someway if it is kept in the Facility and was a contestant for sacrificing the victims of the Cabin. Because the Snowman is not shown at any point during the film or even in behind the scenes, any noticeable features and behavior remains a mystery. How the Snowman was brought to life or where he was created is completely unknown, but its very possible that some sort of dark magic was used with the intent of causing harm to others with a seemingly harmless and friendly thing. Exactly how a snowman would carry out its deadly attacks is also left to the imagination; methods such as impaling victims upon the branches used for the snowman's limbs or magically freezing victims to death would make sense.
The presence of a Snowman would be somewhat inconsistent with the climate around the cabin, so presumably the Facility would have had to manipulate the local weather in order to permit the Snowman to operate.
The item that summons the Snowman is unknown. Possibilities include the components used in creating a typical snowman such as a carrot (used for his nose), scarf, hat, coal (buttons) or sticks (arms). A snow globe is another possibility.
It is not seen during the Purge or anywhere else in the film as mentioned earlier. He is not even seen in behind the scenes footage or in the visual companion book. It is probable that no Snowman props or effects were created for the film, and the entry was made to fulfill a particular category of monster, namely: a playful and harmless childhood object transformed into something dangerous and horrifying.
Possibly a reference to Jack Frost , the Goosebumps book Beware, the Snowman, or perhaps even the Snowman from the Time Splitters series. Another possible reference could be to the popular YouTube prankster ICEMAN, who wears a snowman costume and scares people passing by as a prank. Animated malevolent snowmen appear in the 2015 horror-comedy film Krampus and in a 2012 episode of the television series Doctor Who, although both were made after The Cabin in the Woods.