Mine is home made (1" piece of rebar 6' long with a piece of 1/4" plate made into a chisel tip).
There are some manufactured versions available.
At CT there is a Rapala model: http://www.canadiantire.ca/en/pdp/rapala-ice-fishing-2-piece-chisel-1784200p.html#.VKrRbCvF-So
Jiffy makes several versions as well: http://www.jiffyonice.com/EComStore/catalog/categoryinfo.aspx?filter=1&search=spud&type=q&keywordoption=any&cid=5&fltrdesc=