Aquaman (1967) 1x13

Aqualad finds a city built by a super scientific race. The race turns out to be The Octomen. Aqualad and Tusky are kidnapped by them to lure Aquaman into a trap and find out how he communicates with the sea creatures. While saving Aqualad, Aquaman is captured and forced to reveal how he uses his powers. This gives him an opportunity to call his undersea friends for help. At this moment the trap, an electric octo-giant, is unleashed. Aquaman and Aqualad are forced to find a way of destroying the creature.