A Nut for Marineville is the 30th episode from the Stingray television series.
An eccentric professor is brought in to develop a super missile which is Marineville's only hope of destroying an indestructible undersea craft.
The scene opens as the World Security Patrol vessel "Sea Probe" (or another member of its class of submarine) is on patrol. The ground behind the sub opens up, an alien craft emerges and proceeds to pursue the "Sea Probe" class ship. Inside the cockpit, we find that the craft is piloted by two sub terrainians (one of which is called Grupa). They load their missiles and prepare to fire at the World Security Patrol submarine. Grupa tells his crew mate, Noctus, to make sure the missiles miss their target to which he replies he has angled the missiles the miss the Sub by 5 degrees. Grupa then gives word to fire. The craft fires two missiles, they both narrowly miss the World Security Sub. Grupa congratulates Noctus and tells him to shut down motors. He obeys and the craft glides to a stop as the motors die down.
Grupa then declares them "a sitting target". Noctus becomes nervous asking him if it will work, to which Grupa replies that it must. The World Security Patrol Sub then turns and prepares to attack. Noctus says that doing this is crazy but Grupa assures him that it's "crazy enough to succeed".
The World Security Sub fires its missiles, they hit the craft but it does not fall to pieces. Grupa then proclaims complete success and boasts the metal the craft is constructed from is completely indestructible before ordering his crew mate to prepare more delta missiles but this time to "shoot to kill".
The craft fires and the World Security Sub blows up in ball of fire. Having proved its worth, the craft then sets off. Grupa says that now they are certain that their craft is invincible they can carry out their main plan which is the "complete and utter destruction of Marineville"