It seems like its an incomprehensible monster from beyond. Its not.
Rolling Updates, Up for Grabs, Needs a Better Description, Needs More Examples, Needs a Better Name. redirects:Monster Person, Monster People. A being that for all intents and purposes would fit the Eldritch Abomination mold if it didn't have a human(ish) thought process. Something that "looks" (if it has looks at all) like a sin against nature is nearly always assumed to have incomprehensible motives (which usually serves as a short-hand to kill-it-on-sight, 'cause unknown = "bad/evil"), so when it's shown to have understandable (re)actions, it serves a purpose as a surprise factor for the audience (usually, as this can be played with in other ways). Now, this doesn't mean it can't be a jerk, or an outright (anti)villain, but in any case, it does have comprehensible reasons for it's actions. They may be a Woobie, Destroyer of Worlds, especially if the writer wants to make a point about What Measure Is a Non-Human?. They might even get more emotional torque out of it by driving them to insanity, making it seem like the average Eldritch Abomination to the viewers and characters who don't know. Extra points if the so called "normal people" made it insane in the first place. The biggest difference between this and Starfish Aliens is that the latter are "merely" non-humanoid aliens that can (and usually do) have an incomprehensible or extremely strange mentality, while this type of character can have that whole mind-shattering physical presence shtick while also having a (nearly) human thought process (or, at the very least, it's able to understand it). This is the intended result of many And I Must Scream scenarios that result in Body Horror. Compare Non-Malicious Monster and Sympathy for the Devil. Compare and contrast Eldritch Abomination and Humans Are Cthulhu. Contrast Humanoid Abomination.