Not much is known about Shamgar. He gets one verse in the Bible with little back-story, but one thing is known.
Don't mess with him.
The story of Shamgar comes after a huge epic of sneakery and stabby prose of my main man, Ehud. While the story of Ehud is gripping and capable of modern Hollywood interpretation (shh! Don't give them any ideas!), Ehud still only killed one guy. Yes, he could have killed more that King Eglon, but it's not recorded.
Shamgar is different.
Almost thrown in as a "deleted scene," in the hopefully-not-to-be-made-into-a-movie book of Judges. Shamgar is mentioned as a son of some other dude, (yeah okay), who struck down six hundred Philistines (oh yeah?) with an oxgoad. He too saved Israel. (wait, backup..)
An oxgoad is a wooden pole with a sharp point. An oxgoad could be as long as 10 feet. So, suddenly we see that Shamgar in a new light.
I think "The Message" translates this verse as "And then this guy grabbed a pole and went all "matrix" over those Philly guys. Man, you should have seen it."
Another aspect to the story is that it just ends. We're left to assume that Shamgar didn't give interviews. He simply saw what he needed to do, did it and then went back to work - presumably goading oxes. The others most likely kept their distance, fearing that the nice guy in the field will snap again or something.
He would serve well in a line of Biblical trading cards.