Gade Gade was the Monster of the Week on Ep. 18 of the UFO Robot Grendizer series, and the 19th overall in the show. He was the first among a line of monsters that broke the mold seen thus far in its vehicle modes, in Gade's case instead it was a monster comprise of multiple flying saucers when combine, created a serpentine like creature with the extra feature of having multiple heads to act as replacements or stand ins if the first head was detach and attacking or destroyed. Gade Gade was purple in color, cover in spikes on the head, neck and sides, with turbo thrusters that allowed it fly in its monster form. He could dig through the ground and spew green fire, and with the large yellow spike on its head (an antenna really) could controlled brainwashed humans at any given range. Each portion of Gade Gade, could fire its own Vega Beams.

As the Space Observatory begins work on the new exit route No.7 for UFO Robot, a trucker, a gas service attendant and a police officer see an flying object over the woods. The three (along with a 2nd officer) travel to investigate, where they find the glowing UFO, and when four Vega Soldiers come, one the officers shoots in panic to no effect, in response the Vega Soldiers stunned the four men. The Soldiers then displayed a new ability, transferring their selves (body and conscious) into the bodies of the four men, using them as disguises and head back to town.

The following day, a Reconnaissance team of 5 Minifos are spotted by the Observatory and Koji runs to the farm to board the TFO, when the flotilla attacks. Koji fights them on the TFO, but these disappear near the town. Koji lands to talk to any witness, when he is attacked by the posses men, he fends them off successfully, but when he tries to seek help in the police station only to be taken by an entire squad of posses police officers, Blacki is inform of Koji's capture and orders his agents to brainwash him with an injection and wait for Duke to show up (explaining how the rest of the police, if not the village, may had been possess). By Sunset, with the Observatory receiving no response from Koji, Daisuke is reluctant to help him after he ignored his warning, but takes off to the village to search for him either way do to remorse (making that whole scene really pointless).

Daisuke follows Koji's distress signal to the village, where he finds the TFO in the middle of the town, with him unconscious (so yeah, you know where this is going) and wakes him up. Right at that moment, the ground shakes and the Gade Gade burst through to attack. The two make a run for with the Beast in pursuit, Daisuke uses the defense weapons on the bike to fend off the beast, with Koji providing cover with a missile barrage for Daisuke, who then jumps on the TFO. Koji keeps shooting the beast with missiles and it falls apart. The two depart, Blacki orders the Beast to reassembles and hide underground, having accomplished the first half of the mission.

Once back at Observatory, Koji retires to his quarters, feeling a headache, but sends a transmission to Vega and Gade Gade follows it. The signal is detected and Daisuke and Umon inspect the building for its point of origin, where Koji is found out and knocked out by Daisuke, who grabs the device and ties it to the Jeep, which he allows it to drive off, to no luck as Gade Gade arrives and attacks the Observatory, the Makiba farm and Bunta's house. Daisuke saves the families, then heads to take off on Grendizer, using the newly built Route 7 as the other 6 were destroy in the attack (dunno how, they are all underground, also, in one of the weird moments, Duke's eyes, as well hair, change color and glow green, I actually thought he got possessed, which makes me wonder "WHEN DID HAPPENED?": it was quite a weird thing to put in the launching sequence).

Anyways, Daisuke launch UFO Robot, coming out from the falls, this is confused by Blacki as the secret base, and the Gade Gade flotilla attacks. Grendizer proceeds to knock down some of the Gade Minifos and the rest reforms into the beast – it launches its head to attack while a new one takes control of the whole construct and wraps around Grendizer. Meanwhile Koji wakes up and heads to the Control Room taking everyone at Knife point in an attempt to kill Umon, but Duke destroys the heads of Gade Gade including the one with the Antenna, freeing Koji from its control on time, and the rest of the Beast is repelled with Anti Gravity Storm and finished off with space thunder.

Afterwards, Daisuke tells Koji to not worry about any lingering effects of the Injection, as the Antibodies will naturally get rid of them. The two head back to the farm to help the Makibas fix the damage, Dambei reprimanding Daisuke for his laziness.