Gelumcaedus

A Gelumcaedus (GAY-loom-KY-dus; Grimm: GEL-um-KY-dus; Lat. gelum "coldness" + caedis "kill") is an alligator-like Wesen that appeared in.

Characteristics
When they woge, Gelumcaedus gain thick pale-green skin. Their mouths extend forward, widen, and become filled with razor sharp teeth. Their hair and outer ears disappear, and they gain sharp claws.

Physically Gelumcaedus are incredibly powerful, able to tear a man's limb clean out of their sockets and cause multiple fractures simply by shaking them. Their grip is nearly impossible to escape. They are durable creatures, able to take great force. They are also able to move with incredible speed for their large size.

Gelumcaedus are exceptionally hardy and adapted to live perfectly in dark and severely fetid conditions without any noticeable health problems as a result.

Behavior
Gelumcaedus are commonly known to have dormant periods when they retreat to bunkers fashioned within storm drains and live off of their plunder. One of the oldest known Wesen species, they served in the Praetorian Guard during Caligula's reign and were hired to protect the newly built aqueducts. They carried on in this role throughout Rome's history, as when Rome fell they retreated into the aqueducts to get away. Some speculate this is why they're fond of storm drains.

Gelumcaedus are an incredibly aggressive and dangerous Wesen that will attack with little provocation, using their powerful jaws and inhuman strength to literally break apart those that got in their way. Their typical way of killing has been compared to Siegbarstes in terms of both brutality and strength.

Their relationship with Grimms is one of both fear and respect. They refer to Grimms by their old Latin name, Dēcapitāre, which means "he who decapitates."

Excerpt from Grimm Diaries
''Gelumcaedus is one of the oldest known Wesen. According to Grimm lore passed down from generation to generation, the Gelumcaedus served in the Praetorian Guard during Caligula's reign.''

''Having ventured further into the sewers, we were almost overcome by the fumes. It is easy to see why Gelumcedus chose this place to live.''

Without the breathing apparatus Anna invented, we could never have survived the fetid conditions.

''We were finally confronted by the Gelumcaedus beneath Farringdon Road. The Gelumcaedus had just emerged from a dormant period common for them, during which they retreat into the hellholes they fashion for themselves, living off their plunder.''

Even as the Zeppelins rained down fire on the city above, our battle below lasted us the better part of the night.

''I regret to report that Reginald, one of the hunters we took with us, perished in the fight, his upper limbs torn from their sockets. Escaping this Wesen's grip is virtually impossible. As a result, I have procured a "vambrace" should I ever do battle with a Gelumcaedus again.''

Trivia

 * Despite being rare Wesen, Gelumcaedus are among the most prolifically recorded by the Grimm community.