Octaman

In the radioactive waters off the coast of a Mexican fishing village, scientists encounter a mutant species of octopus with human eyes and an eerie childlike cry. Whatever the creature is, its outraged half-man, half-octopus father wants it back. When a morally bankrupt scientist (Kerwin Mathews) attempts to sell the critter to a circus sideshow, the creature's father stalks his team on a bloody rampage.