An Ork War Buggy.
The driver's head has been cut off and replaced by one from the Ork Boyz plastic sprue.
A weapon sight has been added one from the Ork Boyz plastic sprue.
Spikes have been added to the rear wheels - these are modified choppas from the Ork Boyz plastic sprue. The small spikes that would have originally been on the rear wheels have been moved to the front wheels.
The glyph on the front is from the wrekker trukk glyph sprue