Miata bugeye conversion as seen in Kit Car Illustrated, April 1993.
This product was also advertised in Miata Magazine in 1993. There was even a AH-style grill to go in the mouth. If you look close at the bottom photo, the mouth is not full-open. The Miata's bumper structure is in the upper 1/3 of the mouth, painted black to look less obtrusive. With a grill in place, it would easily go undetected, as cars "fake" grill openings all the time.