Snowman

A snowman was an snow sculpture made to resemble humanoids. The practice of originated on Earth. 

Earth custom
In 2151, Enterprise (NX-01) crewmembers Lieutenant Malcolm Reed and Ensign Travis Mayweather built a snowman on Archer's Comet. Because the Earth Starfleet crew was under open surveillance by the starship Ti'Mur, Reed and Mayweather fashioned the snowman after a Vulcan. 

Q's Winter Wonderland
During the festive season in 2409, q put numerous snowmen in his Winter Wonderland, which he opened to officers from the Federation, the Klingon Empire and the Romulan Republic. These snowmen were often put in fighting postures, with wooden sticks standing in for phasers, phaser rifles and bat'leths. The snowmen resembled several major Beta Quadrant species, namely Andorians, Humans, Klingons, Letheans and Vulcans. 

Later on, q animated the snowmen regularly to engage in friendly snowball fights with the visiting officers. The only ways to defeat the animated snowmen was by using snowballs and snow guns. Once 150 snowmen had been dispatched, the Snowman Overlord appeared on the ice lake, proclaiming himself the ruler of "all the lands of ice and snow." Defeating the overlord required the cooperation of several officers. Fighting snowmen either were basic humanoids with a Starfleet combadge or Klingon. During the fight, existing snowman sculptures were animated and addtional snowmen could spontaneously erupt from the snow.

When q added Gingerbread Colony to the wonderland, the animated snowmen became the enemies of the Gingerbread folk and attacked them repeatedly. Only a five-person team of Allied officers was able to push back their invasion of Gingerbread Colony each time. Leader of the invasion was the Snowman Baron, another overlord but not the same from the snowball fight. Among the rewards granted by q upon defeating the baron was a frigid lump of coal, which had the power to transform an officer in possession of the item into a snowman, but only in Winter Wonderland. 

A Ferengi holiday item vendor in Winter Wonderland offered harmless non-combat snowman pets in exchange for 25 Andorian sleigh bells and 25 Bajoran Gratitude beads. That snowman would only be animate during the festive season and appear alternately in the shape of Andorian, Human, Klingon, Lethean or Vulcan snowmen. Human snowmen would either sport a dark Starfleet combadge or a hole in the centre.