Thunder Gei (Sandā Gei) was a Whale Cyborg Kaiju of Gori's, who was featured in the 17th and 18th Episodes of the Spectreman show: "Thunder-Gei The Flying Whale" and "Infiltrate Monster Island".

_Appearance and Abilities_
Thunder Gei resemble a giant light Blue Whale, with a massive mouth fill with whale like teeth, and two pairs of fins. Given Cybernetics, the Monster was capable of flight, but thanks to Gori's mad genius, elements of the Electric Eel was added into its construct, allowing it to generate and store electricity for its attacks, using it as destructive lightning fired through its mouth or release massive discharges across the body; It also release waves that shutdown electronics; it was capable of mimicry, copying its opponent moves to increase its power and change in size to that of his enemy and even to change its looks to hide as a small island at mere sight, but his mimicry was also the source of its major weakness, which in the end leads to its destruction. Finally, the Monster was able to wrap itself around an invisible barrier that allowed him to disappear, as well deflect radar waves, and attack without warning, though the use of of its electrical attacks weaken down the Invisibility shield, looking like a assemble particles of Electrical Charges.

Thunder Gei's roars were slowed down roars from the Dinosaurs in the 1960's The Lost World and the Voyage to the Bottom of the Sea tv series. The Kaiju was performed by a prop, and was the first monster in the show to be killed by Humans rather than Spectreman.

_History_
A Fishing trolley out at sea stumbles upon a large whale it can't detect on radar; the Monster whale rises to the sky and uses its electric waves to shutdown the trolley and blasts the vessel with its Energy wave, but not before the Captain sends a message via radio of the creature. The news of the disaster reaches land, where the Trolley Captain's children (Tommy and Margaret) are inform by their Grandfather of what had unfolded, however, The family of the Captain takes slight as the media questions his competency for the whale story, specially Tommy, who George sympathizes with, though the boy comes to be tease by the other kids later on.

(Seventeen Fucking Episodes in they pull this shit up – I hate when these shows do this, when by this point there are so many attacks, Monsters are a fact you can't question them in universe.)

As news of Thunder Strikes of destructive power come from other areas, George comes to suspect Gori is up to his old tricks again, so he decides to investigate the matter and sticks around Tommy and his grandfather, hearing his tales of his ability to see things others can't see when a lightning strike destroys a trolley and wounds the old man's eyes, but he is able to see the Assemble of Particle Charges of Electric Waves that cover Thunder Gei. George, Margaret, Tommy and the Grandfather follow the Lightning Storm to the city, when all the cars and electronics shutdown. George recommends Margaret to take her family to their bureau to explain everything, while he leaves to hunt down the Monster as Spectreman.

Using its Spectre Lights, he reveals the Whale to himself and smacks onto it, only to crash back to Earth, hitting a Truck in the process, as Gori and Karas watch the show from their ship; Spectreman then grows even larger and so does Thunder Gei; The Cyborg smacks it again and again, been repelled by his thick hide to no avail. Meanwhile, the Grandfather and Tommy explain the situation to Kurata and the others, and come to learn of the Electric Waves that cover the creature and head to the roof to see the battle when Spectreman uses its Spectre Flash to reveal the Monster to the whole city, but crashing back to the city, Spectreman faints and Thunder Gei leaves the city and dives into the sea, with all surrounding Electronics in the area returning back to Normal. The Monster changes its appearance to that of a small island, as Gori plans to have it suck all electrical power from the nation to sow chaos across the Earth, while George returns to the Bureau wounded.

Not long after, news of the new island make George, Margaret and Tommy suspect its the whale; after been rejected by Kurata following his injuries, he and Tommy go to the "island" to investigate it, avoiding soldiers guarding the area. Once there, they find a glowing device, but come under attack by vines and the two fall through a hole and are trap inside the Monster, where after a brief exploration, they find the Energy Storage Center; in that moment, Arthur, John, Otto and Margaret drop a rope to help them out – the quartet having come to the island under Kurata's orders knowing George was going to do so despite his recommendations. Immediately, the whole group comes under attack by two of Gori's Ape Men – they beat them and escape the island, just as Thunder Gei transforms to its true form and proceeds to attack the Coastal Village.

Taking the chance after separating from the others, George transforms into Spectreman, then begins to study the creatures habits and comes to see that whatever he does the Whale mimics. So he begin to decrease his size and thus the Monster shrinks as well. So Spectreman weakens himself and Thunder Gei does the same; he pass this information to the his human friends, suggesting to set powerful explosive; as they head back to the Monster to carry out the plan, Spectreman comes under attack by Karas, taking advantage of the situation. Tommy sets the bomb on the Energy Center, the group runs out of the Monster and escapes – seeing this, Spectreman proceeds to beat the living hell out of Karas, as Tommy presses the Detonator, destroying Thunder Gei and avenging his father.

Time later, The Grandfather had recovered and Tommy dreams of his Father a lot, though he got back at the Monster who killed him.