when they're in the empty pool examining a corpse that has mutated into the wall, we can see that there's an ouroborous tattoo on the corpse's forearm, which is also the same tattoo Anya has, also the same tattoo Lena has on her forearm but only after she leaves the shimmer. what does this mean?
also, what do the shimmering eyes at the very end mean?
The corpse decorating the wall is the most visual sign of horror and death. It also indicates the fate of Anya and she got that message clearly. Many horrible things happened in area X. Still, Lena tried to convince the scientists that the alien was somehow innocent. As if it didn't know what it was doing. If you don't buy that BS, then the question remains "Was the alien evil?". The tattoo provides a hint to the answer: "It represents the infinite cycle of nature's endless creation and destruction, life and death." One might argue that it is the reason behind human self-destructive nature. As Lena mentioned it to Kane: "They say aging is a natural process, but it's actually a fault in our genes."
At the end, the shimmer in Lena's eyes reveals that Lena was infected and changed to something new. Which is a open ending - some might take it as a happy ending and some other might think it will lead to a catastrophic event.
The way I understood it, in the end, was that Kane AND Lena were both mutant clones from the Shimmer. When she asked him if he was "really Kane", he answered "I don't think so". That could be why Lena went to hold him since it probably made them feel less alone since they were two unique creatures from the Shimmer.
And I do get these mutation/replication things but what about the tattoo that magically appeared on Lena's arm? As I remember it, only Anya had it in the beginning. And tattoos don't change any DNA structure so replication/mutation couldn't do that, I think. Would the Shimmer "see" that on Anya's arm and then mutate Lena's DNA to make the design appear on her arm? Maybe but that wouldn't make sense.
If someone has a satisfactory explanation about the tattoo, please do share.
What the symbol represents has been explained- in short, the balance between destruction and creation in nature. Lena's having exactly the same tattoo as Anya indicates that it is not random as the physicist later explained, instead the alien can precisely alter anything they want in the Shimmer. To do that, so-called "Everything is connected" actually means that the alien can sense everything in the shimmer including human's dreams and thoughts. Anya, who is a lesbian, had a crush on Lena after she'd bravely saved them from the mutant crocodile. Right after that, the alien put her tattoo on Lena's arm as a pairing label, like what we do on the lab rats before starting an experiment on them. The goal of this experiment is to understand the complexity in human relationship, in order to fix the relationship between Kane and Lena. Why did the alien want to fix that? The tattoo is a hidden clue from the author- In the Shimmer, we find some beautiful creation of plants and animals, but when it comes to the human, there are only dead and degradation. Which should make us wonder: where the hell is the creation that balances out the destruction? From my understanding, for human, if destruction means dead, then creation could only mean one thing: newborn babies. From the ending, it is not hard to imagine what will happen next. Whether the parents are half human half mutant or something else doesn't that matter as long as those babies are a better version of human. If those babies are supposed to be "destruction" to humanity, then emphasizing the symbol of the tattoo would make no sense at all.
shareWell, one of the "points" of the movie was growing from a single cell into multiples.
Kane alone = oine cell
Kane + Lena = two cells
Their possible offspring (say, two of them) = four cells
etc.
Until eventually (depending on their lifetime/cycle), the entire world could end up being populated by Shimmer cells.