Motel Hell...  truly a classic of its time.  I really do not know if this was intended as a partial comedy or not, but parts sure are funny.  What a classic.

Farmer Vincent kidnaps unsuspecting travellers and is burying them in his garden. Unfortunately for his victims, they are not dead. He feeds his victims to prepare them for his roadside stand. His motto is: It takes all kinds of critters...to make Farmer Vincents fritters. The movie is gory, but is also a parody of slasher movies like Last House on the Left