Hunt in this location: Vacant Lot > Great Winter Hunt event
Note: This mouse can be attracted after breaking the ice of Snow decoration
Tasked with the tremendous responsibility to gather snow for any and all winter festivities, the Snow Boulder Mouse works tirelessly rolling up mass amounts of snow to be used as ammunition for their invasion.
They have also been known to roll up one or two of their brethren. It's tough enough to roll up the snow, let alone watch where you're going!
Mousehunt Wiki page