Gama were various members of the Frog like Alien Gama Race, who appear in Episodes 46 and 47 of the Spectreman show; Invitation from the Dead and Alien Gama commence the attack.

The Gama were a humanoid Frog like alien Race who sided with Gori in his plans to conquer the Earth for the promise of food sources, namely people and took base on the island of Arthur's Grandparents, capturing and eating some of the inhabitants.

The Species came in variants; the aforementioned Alien Gama, which are Anthropomorphic, Humanoid in aspect, bipedal, but with Frog Heads; The Young Ones, which resemble Frogs, albeit far more bigger than normal frogs, and finally Lord Gamma (Gamagaeru), which was a Kaiju version of the species the Aliens revered, enormous in size. Two versions of this creature were seeing in the story line, the 2nd been comprise of all the Gama joining as one, possibly indicating the origin of the 1rst Gamagaeru.

The Aliens where capable of Combat, albeit this ability worked in Numbers, and were talented masters of Disguise, although, Cameras could reveal their true identity.

The Smaller ones were far bigger than normal frogs, but their hunger was voracious, and like Piranhas they would gang up on a prey and devour it.

Gamagaeru would use strength and Spit as weapons.

All the Gamas produced the same vocal sounds as Frogs.

History
Following a Survey plane crash, Arthur, along with George and Kim, travel to his Grandparents home island for a visit on the old folks and some R&R, but things aren't what they seem as he learned some acquaintances had died or left, and his Grandparents act strangely; George is the first to come to see this when they dispose of the Fish Arthur brought them and proceed to eat a basket full of crickets with extendable tongues; these impression worsen as at one point they are surrounded by odd looking Frogs. A visit to the cemetery where to lay flowers to his late friend, Kim is startle by the strange Frogs, who seem to keep eyes on the trio.

Meanwhile, a Photo reveal from the Survey Plane crash, shows the two elders saluting back at them were Frogs; Kurata and the rest try to contact George and the others with no avail, so John and Otto travel to the island to warn them.

That night, following another strange encounter with a "Friend" of Arthur and An argument with George about what he saw of his grandparents, the trio comes to see what the Villagers really are as they dispose of two men, been devour by the frogs; back at the hut, Arthur can only accept the fate that befell the real inhabitants, just as a passenger plane flies over and explodes; with the situation been grim, the trio are force to escape. The next morning the trio attempt their escape of the village under the pretense of going fishing, but soon come to realize they are making circles, worst witness another human being been captured and then fed to the frogs; they try to help, but are cornered by the Villagers, who reveal themselves as Gama Alien.

Arthur, Kim and George fight their way out, with their weapons having no effect on them and in the scuffle, the Lord Gama himself appears, desperate to eat; George is able to squeeze his way out, and transform into Spectreman and battle Gamagaeru while Gori and Gama have a meeting; the encounter was brief and it ends with Gamagaeru (presumably been killed) and our hero's power depleted and reverting back to George.

Later, George awakes in a prison, with the Gama demanding to know who of the three is Spectreman, since he was not destroy in flight by their Ultrawave Deflector Shield – this device is what has been taking down the planes. They summit the trio to torture via Electrocution, but all three come negative (including George, due to his low energy state). This situation forces the Gama to commence their invasion plans ahead of schedule and transport their Frogs on the major cities in Japan, just as John and Otto arrived, but soon have to take a detour due to the fallen bridge – in fact a ploy of the Frog Men.

At the prison, the trapped trio try to get the fallen key from the guard using Kim's Nylons, a Frog and Worm as bait; they succeed, recovered their weapons, but on the way out, the come to see another jail with villagers, including Arthur's Grandparents alive; he wants to rush to save them, but the Escape alarm sound off, making everyone aware of their escape. The group takes down one of the Frogmen and takes its clothes to have Arthur and manage to pass the checkpoints; he nearly succeeds before been found out and is force to fight his way out and runs to John and Otto; all the Gama Alien disappear. He successfully report everything to Kurata and the chief seeks the advise of a Frog Expert who comes with a solution of Sodium, Mercury and Lead, poisonous to Frogs been used on Spray Guns. Arthur, Otto and John then carry out the attack, killing some of the Frogs on the island, while Kurata repels all the Gama that came on the Ferry with JSDF Servicemen.

With their plans ruins and putting the blame on the Gama for the escape of the G-Men they held, Gori has all the Gamas, big and small, fall into a vat that combines them to create a new Gamagaeru to reek havoc in the harbor town; with all the frogs gone, this allows George and Kim to return to the cave to free the trapped villagers, but the solution poisonous to Gama has no effect on the new Gamagaeru and the beast makes its march towards the city, with the whole of the Pollution Squad teaming up and following it.

The situation goes from bad to worst, as a train lies in the path; George breaks from the team to stop it, but misses the train. Despite been just 90% recharge, George transforms into Spectreman and battles the Giant Frog in a refinery, with his friends cheering from the sidelines, Spectreman tosses the creature into the bay where he continues the beat down of Gamagaeru – but in a fortunate turn of events, the Salt content in the water gives help to our hero as the Giant frog begins to melt away. The turn of the battle disappoints Gori, who hightails out of there.

Time later, the Squad is able to take the trap Villagers for a boat ride.

How did this Motherfuckers were going to conquer a planet that is 2/3rds Ocean?