The creator of this probably started out designing a belt-fed machine gun before deviating only slightly. A water coolant jacket would probably be suitable looking at the magazine and bolt travel distance. Apparently sold to an out-of-town gang for $800 BR.
What appears to be a home-built copy of the TEC-9 / DC9 pistol seized by police in Canada. The upper receiver appears to have overly crude welding and lacks the distinct barrel lug stampings of the original while its lower receiver has a flat non-standard profile. The open position of its bolt suggests it is likely fully automatic.