Name: Neuroparasite (Pisca)
Appearance: Neuroparasites, under a microscope, look somewhat similar to fleas. However, they are eyeless, have a body shape somewhat similar to a red blood cell, and their six legs are meant for attaching and embedding themselves into a host. They have a frail little shell to protect them, but as they are very smart, it is incredibly difficult to corner them, and due to their size, crushing them is just as hard. They can go for long periods without sustenance, and do not need to breathe, as they gain oxygen and nutrients from the blood of their hosts. Because of this, and the constant firing of neurons warming their little bodies, they can survive the vacuum of space almost indefinitely.
Like Pisca, Neuroparasites as a species need a host. They enjoy learning more than anything, and due to inheriting the knowledge of their parent, they are starting to disperse to new galaxies in order to find new knowledge and new hosts. Larger hosts are better at sustaining themselves and a Neuroparasite, though the smallest host so far has been Alice, and she's doing quite well.
When it comes to psychic links, they will not form one with a host if they are simply using them for sustenance. However, the flawed, emotional little beings they are, they can choose to stay with a host until the host dies. Often, they do, as contact with those of their own species is a somewhat rare occurrence, and they do get lonely. Links with a host can be either quite shallow, or unbelievably deep. Some of the deepest links are also the most empathic, and in rare cases, a Neuroparasite can temporarily control the movements of their host.
Attitude: Having mentally evolved through hosts and rare connections with others of their kind, neuroparasites do have different personalities, and will sometimes identify as one gender or another, depending on the opinion of their host. Pisca in particular has difficulty connecting to his own emotions, needing a host not just for sustenance, but for support as well. He is quite an aggressive little thing, extremely defensive of the host or three he's had in his life, and always devastated when their life eventually ends (as neuroparasites do not age). Like all neuroparasites, he was given his 'mother's' knowledge that she had accumulated through life when he was born, and nothing more.
Technology: Neuroparasites are technically hermaphrodites, and reproduce asexually. As they are so small and spread-out over M-74 and Andromeda, they have no real society, laws, etc. Two neuroparasites meeting each other is a rare happening, as they tend to disperse, and only make a few offspring at a time. Due to having limited telekinesis for movement purposes, and telepathy as their sole means of communication, they are mostly brain. They enjoy learning, but have no reason to need or want any technology of their own.
Backstory: Pisca was born in the Pisces constellation in the M-74 Galaxy. Like all neuroparasites, he left his 'mother' at birth, and intended to travel to the Andromeda galaxy, as M-74 was getting a tad too overpopulated for his liking. However, he was taken off-course by a large ship that appeared to be heading that way as well. So, he latched himself to the outer hull and rode along. Unfortunately for him, this ship (belonging to the Sontarans) had a course laid in for Earth. Alone in this new galaxy, the Milky Way, the still-nameless Pisca made his way to earth after the Atmos incident. Meeting an 8-year-old human child who called herself 'Alice', the parasite immediately felt a sort of connection when he first established psychic contact. The ever-curious human began to enjoy him and his presence, so when he offered to stay, she accepted. An emotional turning point from his cold little exterior was when Alice decided to name him. Having a name that related to his birthplace mattered little to him, but the fact that Alice had made a name specific to him and his (admittedly short) life story made him happy for possibly the first time in his bad-tempered life.
Present: Pisca, no longer nameless, has found a host he connects with on a psychological and emotional level. While he is really on a lean diet to avoid accidentally hurting or killing Alice from undernourishment, he finds that he doesn't mind quite as much as he should. He enjoys talking with her, seeing through her eyes (as he has none), and can even establish temporary empathic links with Alice to give himself pseudo-sensations.