Could it be from KRAI THONG? I know most of the time it's listed as a 1980 production, but the scenes that are on both films are longer in KC and seem to be better integrated to the story than in CROCODILE, suggesting they could have been shot specifically for KRAI THONG. There is also a head prop used for the water scenes, and the one with the red eyes.

Regarding the direction, who is Le-Won-See exactly. CROCODILE/HORROR OF THE ALLIGATOR seems a bit out of place in his filmography, which seems to consist on dramas mostly.