Waterborn mind-controlling parasite, name tbd

Some things... were never meant to be found.
Much was corrupted by the Deceiver back in the early days of Eldûra. Thus was how this blight was born.
In deep, waterlogged caves located under the Dragonstone Mountains, these parasites lie in wait for suitable hosts. They have never forgotten their master's desire to destroy what the Creator had created, and they desire nothing more than carry out his plans while also gaining control over the unknowing masses. These creatures are narcissistic, arrogant, and conceited, and somehow view all other forms of life as lesser than they despite the fact that they are nothing more than a tick-sized creature.
They gain control over their hosts by latching onto the backs of their neck, where they pierce the skin with a long telescoping tongue that burrows all the way to the host's spinal cord. There, they override the host's mind and take control of their body. Once done, the parasite camouflages its body so as to remain invisible from prying eyes.
Dwarves are the only intelligent species that they cannot control. A dwarf's skin is simply too thick for them to pierce.