Scorpion Man is a scorpion monster, he was originally known as Goro Hayase (an old friend of Takeshi Hongo) who uses his old identity to approach and attack Hongo. He controls an army of robotic scorpions that release corrosive acid. Has the ability to burrow underground and uses his pincer as a weapon. Destroyed by Kamen Rider #1's Rider Scissors.
He was later resurrected by Shocker as part of the Revived Kaijin Army and faced Kamen Rider #1 again, but Hongo fought without hesitation and easily beat him in their second battle. He was destroyed afterwards by the detonation of Tokageron's special bomb. Tokageron and the Big Monster Army Scorpion Man also made a brief return appearance in the monster army of the Kamen Rider vs. Shocker movie, but did not actually have an active participation there.
Super Hero Taisen
Scorpion Man was revived as part of Dai-Shocker in the Super Hero Taisen incident, led by Tsukasa Kadoya/Kamen Rider Decade, rivaling Captain Marvelous/Gokai Red and Dai-Zangyack. However, Rider Hunter Silva of Dai-Zangyack and Doktor G of Dai-Shocker overthrew their respective leaders and joined forces to destroy the Kamen Riders and Super Sentai. The two evil organizations united and faced off against the combined forces of the Sentai and Riders. During the final battle, Scorpion Man was killed by Kamen Rider OOO's finishing attack with his Medajalibur, the OOO Bash along with Hades God Dagon, Ghoster, and Isoginjaguar.
Super Hero Taisen Z
Scorpion Man have revived again and be part of Space Shocker member.
Kamen Rider Taisen
Scorpion Man revived once again with other Kaijins, and join Underground Badan Empire. He led force by Tiger Roid, Yamaarashi-Roid and Kamen Rider Fifteen to invade the surface and attack the Armored Riders to kidnap Shu for plans. When the Space Break System has risen, Generalissimo of Badan summon other Leaders, Kaijins, henchmen army to eliminate Ryo Murasame and Gaim. Ryo reveal Heisei and Showa Riders that they supposedly been defeated had in fact been sent to Helheim Forest, to help support Ryo and Kamen Rider Gaim.