The Octopuses from the Second Floor (1986)

Original title: Die Tintenfische aus dem zweiten Stock

While on vacation with their bickering parents in Portugal, Eva and her little brother Johnny find two strange clots of clay on a polluted beach, who can speak and move on their own. They create two octopuses out of the blue and green material and take them home to Prague, soon discovering that their new pets attract electricity and other disasters.