The Lisa Snowman was a premium decoration available only for a limited time during the Christmas 2012 Event and returned for the Christmas 2013 Event. It was a prize on the Holiday Wheel.
It returned as a craftable reward in the Winter 2015 Event.
It returned as a rebate offer during The Invasion Before Christmas 2017 Event. It gave a bonus of 10 donuts after purchasing.
Season 7 Christmas Episode: Marge Be Not Proud