A very easy way to make a groundbreaker is to just use 3/4" pvc and just find a cool mask you like and some hands. For just a half body groundbreaker you just need (1) 3/4" 4 way cross connector,and 4 of either 90 or 45 degree elbows (to be used for the shoulders and elbows). Cut a length of 3/4 pvc pipe at 18 inches for the spine,(2) pieces at 7 inches for the collar bones,(2) pieces at 12 inches for the biceps,(2) pieces at 11 inches for the forearms, and you will need (1) piece at between 4 -6 inches for the neck to stick a wig head on.
This is a very cheap way to go for the pvc but depends on how expensive a mask and hands you use.