Snowgies

The Snowgies (also known as Snow-Babies) are tiny, mischievous snowmen that were created by Elsa when she became ill. They are created every time Elsa sneezes. They debuted in the short, Frozen Fever.

Frozen Fever
The Snowgies are created as Elsa starts sneezing. The more Elsa sneezes, the more Snowgies appear. The Snowgies then go to the castle, where they cause some mischief. Luckily, Kristoff and Olaf manage to get them to behave and even have them perform a surprise for Anna. After a wonderful birthday party, the Snowgies get taken by Kristoff, Sven and Olaf to live in the ice palace with Marshmallow.

It also shows Olaf naming each one, such as;  Sludge, Slush, Slide, Ansel, Flake, Fridge, Flurry, Powder, Crystal, Squall, Pack, Sphere and William?

Trivia

 * Like Olaf and Marshmallow, the Snowgies represent a certain element of Elsa's personality, in this case, her long dormant mischievousness and fun-lovingness.
 * Strangely, Olaf can be seen with his flurry throughout the short, while the Snowgies move throughout the courtyard and castle unharmed by the warm climate. It's unknown why the Snowgies do not melt, despite being in the hot weather of summer. This contradicts with the first movie, where, if not for his personal flurry created by Elsa, Olaf would have been melted after Elsa restores the summer.
 * One of the Snowgies has Baymax's face.