This is one compact custom tank built by Tommy Styrvoky, full of motorised goodies inside with a working mini mine-clearing flail outside.
It's a 1/18th replica of the M4 Sherman, a tank used in World War II, fitted with a special flail that helped passing through mine fields safely. The flail's not just the only motorised thing in this LEGO version: the turret has a 360-degree traverse, the gun can elevate and the vehicle has a two-gear transmission with electronic braking. Pretty complex features for such a small build. Here's a short video (and a few cool shots over here) showing how it works (via Eurobricks):
[Images via Flickr]