it's called a whomper, you can make it yourself if you have a welder, a 6ft steel fence pipe and a piece of 1/4 inch steel 24in wide by 14in high, cut a 1/4 slit in one end of pipe insert steel plate and weld to pipe, sharpen end of steel plate and whomp away.
This is CABL.com posting #249891. Tiny Link: cabl.co/mbdaF