It's a TANK!

A disgruntled muffler vendor modifies his bulldozer to take revenge on those who wronged him.

http://uk.youtube.com/watch?v=PZbG9i1oGPA

http://www.headinjurytheater.com/article80.htm

http://uk.youtube.com/watch?v=SbAhF2-H0ew
-hastily hides giant mutant bulldozer behind back-
:'D