Here's a picture.
http://www.miniarcade.com/mattel/horse.htm
My wife bought me one from eBay a few years ago as a gift. Came with the box and everything. It is very cheesy and does essentially pick the chalk, by the same means the chalk becomes the chalk (placing in recent races, etc...).
I'll probbaly keep it forever becasue it was a gift and becasue it is a piece of handicapping history.