Snowflake
From Nookipedia, the Animal Crossing wiki
Snowflakes are items in Animal Crossing: New Leaf and can be found randomly in winter, when it is snowing. They slowly float, similar to butterflies, although a bit slower. They can be caught with a net. Snowflakes can be sold for 500 Bells or to obtain a piece of furniture from the Snowman Series. To obtain the furniture, the player must find two snowballs. Of course, it must be winter for this to happen and the ground must be covered in snow. The player must build a Snowmam, the second-to-smallest type of "snow-person." The Snowmam will ask the player to fetch five snowflakes. Once the snowflakes are given to the Snowmam, the player will receive a piece of Snowman-themed furniture.