Snow Spikes are a sub-species of Spikes, first appearing in New Super Mario Bros., in World 5. Their attack pattern is similiar to a Spike, but they throw snowballs rather than spiked balls. These snowballs can roll through the snow, and gradually grow bigger until they are destroyed.
Returning to the Cold
Snow Spike appears playable in Super Mario MHL. It's special move is Snowball Smash (it throws snowballs at other players).