These were the monsters in the Mutant Mania traveling circus. They include: Medusa, Giant Gila Monster, Scorpio and several other unnamed monsters, such as a horned toad-like creature and a rodent-like monster.
Dehydration: By simply touching prey, Medusa is capable of absorbing the water from a victim’s body, or even water in general. The more water she absorbs, the larger she grows.
Melt: Medusa can turn into a liquid state at will or will automatically melt when being introduced to a heat source such as fire.
A mutated anemone found on a pacific atoll by mutant circus owner Tobias Wilson, the creature, dubbed Medusa by her captor, was put on display for the circus to enjoy. On one such show in New York City, Medusa got free by turning into a liquid form. H.E.A.T., whom was watching with Tobias, was quickly on the offensive and soon the mutant was on the rampage, draining people dry. While her victims were revived with massive amounts of water, the creature continued on, wading through military might unlike that of any other.
After being forced to melt, she entered the subway system and then the water reservoir. The electric fence only made her melt yet again and she entered the city water supply and quickly began to grow. Godzilla arrived just in time to fight, but his atomic fire made her melt and cover him, draining him dry also. She escaped and left Godzilla for dead.
She made it out to sea, but Godzilla, revived thanks to H.E.A.T. and the military, was again on an attack. He repeatedly blasted the anemone, preventing her from reshaping or even making an attempt to strike again. When Nick called him back, the Heat-Seeker quickly moved in, sucking up the liquidated Medusa with a huge vacuum meant to clean up oil spills. With heated coils inside, Medusa was trapped inside. What ever happened to her remains unknown.
Found in an unknown location by Tobias Wilson, owner of a mutant circus, the Giant Gila Monster was captured and put on a display. Using the excuse he was teaching the public about the creatures, he had his crew train his pets. The Giant Gila Monster, along with other mutants, were forced to do tricks and perform until Medusa, a water-absorbing mutant sea anemone, escaped and created all sorts of havoc. With Tobias Wilson captured, the circus was shut down and whatever happened to his captive creatures remains a mystery.
Scorpio was yet another of the monsters part of Tobias Wilson's circus. As the name suggests, Scorpio was a gargantuan scorpion who was similar in appearance to Ts-eh-Go and the Mutant Scorpions, making some believe he could an escaped or stolen specimen from the "Third Wave" of mutant scorpions. Scorpio had been trained to do tricks to impress audiences. What happened to Scorpio after the Medusa affair is unknown.