You know Jack if you've ever read a copy of MAD magazine. Big heads, skinny arms and massive feet. Film spoofer supreme. But it's the work he did for EC and Creepy that really floats my boat. The horror stuff. Look at this panel below from 'Foul Play' - it almost singlehandedly bought about the notorious Comics Code in the 50s. Kids could buy this gore filled fun on their local news stand.
I recommend Fantagraphics collection of Jack's horror strips HERE