Rob Scallon and a horse Source Rob Scallon is just an ordinary guy that plays the guitar really great and makes youTube videos, who decided to cover Slayer songs with unusual instruments. Last week the artist posted a video of him covering Slayer’s War Ensemble with an ukulele. This time he went even further covering Slayer’s well known Raining Blood using a banjo. gotta give the people what they want, and apparently that’s metal covers on…