Reigubas

Reigubas is the giant monster that was worked together with the Spume and Digons. Although it was classfied as space sea monster (宇宙海獣), its true origin is never reveal.

This bipedal monster is greatly resemble Earth's Crustacean and is adept swimmer. Unlike Earth's Crustacean, however, Reigubas can survive in extremely cold temperature. In addition to its powerful pincer claws, Reigubas can use its breath weapon in combat. Spitting gas with extreme temperature, Reigubas can launch either volley of fireballs which accurate enough to hit targets as far away as Earth's orbit from the ground or super-cold ice mist which can freeze Ultraman Dyna within seconds. Apparently, Reigubas can control its breath weapon at will, as its red-glowing eyes will turn blue whenever it's about to use the ice mist.

In Ultraman Dyna
After successfully raided one of Super GUTS's (Global Unlimited Task Squad) Antarctica's base, a giant squid Spume attack another underwater base, Krahkov, during Super GUTS's rescue operation. With its power, Spume has takeover Krahkov's computer system and alter the course of a space station to make it collide with Earth. When Ultraman Dyna was about to attack the Spume, he was ambushed by Reigubas.

The battle quickly move onto land and Dyna seem to has advantage at first. However, Dyna isn't aware of Reigubas's breath weapon and was frozen by the ice mist. Without Ultraman on its way, Reigubas use the fireballs to shot down Earth's fighters that try to destroy the space station in orbit. However, one of Super GUTS fighter lures Reigubas to shoot its fireballs at frozen Dyna and free him. The two giants crash again, though Dyna soon run out of his power. However, Dyna manage to recharge his energy using reflector on the space station. he finally defeat Reigubas by send it into another dimension with Revolium Wave.