Froslass is a slightly humanoid Pokémon that appears to be wearing something resembling a kimono. Froslass's entire body is located on its head and not the "dress" that she appears to wear, as the Pokédex states that "what appears to be its body is actually hollow". Over the top of its head is a type of mask with two "horns" made of ice. On this mask are several openings, one for its mouth, two for its eyes and one in the center of its forehead, all of which reveal its purple "skin" (which are actually hollows) underneath. Attached to the sides of its head are its arms which increase in width halfway down the arms and ends at the wrists, enforcing the look of a kimono. On the center of Froslass's dress is a large, tied ribbon or obi, fitting in with the kimono theme. Shiny Froslass are brighter than the normal ones and her ribbon behind are now pink.
All Froslass have the ability Snow Cloak which will raise their evasiveness when the move Hail is used.
Unlike Snorunt or their other evolved form Glalie, Froslass is a Ghost-type in addition to an Ice-type, allowing them to learn a number of moves the other forms cannot learn.
Froslass searches for unwary prey and victims in snowstorms and freezes them into ice statutes. Sometimes it loves to show off the corpses of the victims that it has killed. Nevertheless, it can be extremely protective towards the things it adores, especially its children.
Froslass is one of the evolved forms of Snorunt. Only a female Snorunt♀ can evolve into a Froslass with the use of a Dawn Stone.
Froslass made her debut appearance in The Drifting Snorunt!. She appears to Ash and his friends while they are traveling through a snowstorm. She creates an illusion to lure them into a trap so that they help find her lost friend, Snorunt.
Froslass is tied with Gengar for the fastest Ghost Pokémon with 110 in their base speed stat.
Froslass and Cofagrigus are the only Pokémon in tournaments that their Pokémon name is banned because of the words in their names.
Given its gender, types and appearance, Froslass are likely based on the Yuki-onna (雪女 snow woman) from Japanese folklore. Yuki-Onna is said to be a spirit that disguised itself as a beautiful woman to attract men who were lost in snowstorms, then freeze them and take their souls as prize. It was often depicted as wearing a white kimono. They are said to be ghosts of explorers lost in the mountains.
Froslass's English name comes from a combination of the words "Frost" (snow or ice) and "Lass" (girl), similar, in the way she is fashioned, to her Japanese name. Her Japanese name, Yukimenoko, comes from combining the words "Yuki" (snow) and "Menoko" (girl).