Mercurius mounstrosity, or project 641 was a last ditch effort to capture or even neutralize the Jellus mounstrosity, that escaped 1 week before the creation of this brand new S.T.S.
It was created using the Periodicmogus called as Mercurius, a liquid metal that can easily change its form. Its more agile and resistant form of Jellus, that can also propinate considerably stronger hits. The only thing Jellus mounstrosity beats it is about its body-shaping, cause Mercurius has no forms of shapeshifting.
It can be configured in two forms: Automatic (it will act for itself with an AI, not fully developed and may be dangerous) and manual (someone will control it in a special room inside its head, way safer form).