There's something big and something hungry living in the still, murky depths of secluded Hillbilly Lagoon...and it walks on land!  Following a toxic spill, science students from the state university are sent in to test the waters for contamination.  They are immediately set upon by insane and inbred locals, who don't take kindly to strangers nosing about their town and beloved lagoon.  But that's the least of their worries when a hulking humanoid borne of radioactive mutation ascends from the inky blackness to fill its lungs with air and its stomach with human bait.