Spoiler alert. I rarely watch series because it's too time consuming and I'd rather be doing something else. However, this one piqued my interest because I knew a bit about the real story so I watched it. Very well made of course, and well acted, but the supernatural element spoilt it in a way I thought. Obviously after the ships are lost their real fates become conjecture, but I felt there was a story to be made without the creature - which only turned up at convenient times in the narrative anyway. Set design and atmosphere were great, but perhaps I'm just not a fan of genre-mixing.
I thought it was there as a representation of their descent into madness and psychosis induced by starvation and poisoning whilst also indicating to the possibility that it might be real, or at least real in the collective group insanity that they're all feeding into in their own ways. It's also possible to read it as a physical embodiment of the hostile environment that's gradually destroying them, especially since it's issuing out of the indigenous mythology of that place since it's a creature kind of made by and reliant on the landscape. In this sense it doesn't matter if the tuunbaq is real or not it's more about its symbolic character. Then there's the fact that it's unknown what happened to them and it being just introduced as an interesting idea, albeit beyond anything else in the story since it's so supernatural. Following that final point I do agree about it being extraneous and diluting the realism of the story
Watched Page Eight on Netflix, very good 8.5/10. Part of a trilogy called The Worricker Trilogy, have to hunt down the other two now.
Good analysis It was very much like an old film called Forbidden Planet if you've seen it. Have you watched "Them" yet? Very similar also in that sense.
Ta Forbidden Planet? Course, classic film. That's a good comparison and thinking about it there's the fact that FP is based on The Tempest somewhat, which is an even older example of a drama interested in quite similar themes. I saw Them as well ... thought that was utter ****. I certainly agree with your point though. The unknown malevolent force or monster is I guess a pretty common trope in Sci-fi. I have other examples in mind but can't remember the names right now.