As a WMG subpage, all spoilers are unmarked as per policy. You Have Been Warned.
I know, the calm and collected Halara is scared of spiders, a crazy proposition... but it fits with how they behave and the rest of their character traits. The seeming hidden anxiety and the affinity for cute domestic animals, it indicates that the sight of a spider can legitimately freak them out. We get no proof of this, of course, what with there being no actual spiders present in Rain Code. Also it's a common fear, and since Halara was once more innocent a time before, one can assume they still have it. It's quite primal.
...Granted, as the literal CEO of Amaterasu, he has all the power to make whatever he wants. But I suspect that he took the gas that Dr. Huesca formerly had for his security and used it as part of his trap.
Sequel Theories:
So the popular theory that DR characters are homunculi because of pink blood can easily be proved false, at least for Hope's Peak Saga. Homunculi are Weakened by the Light, yet characters are exposed to sunlight in 2, several scenes of Despair Arc and in the outside part of the school in V3, but nothing happens to them and they don't attempt to hide. They're also not pefect homunculi like Makoto from this game because they treat mortality as final (Makoto Naegi comments he won't be able to ask Sayaka her true intentions, Kaito dreams of going to space before he dies, etc.). Not to mention, blood is described as red in-universe in 1 and is indeed red in Future Arc. They also can't be originals who replaced their homunculi selves since Future characters remember their killing game. Homunculi inherited originals' memories up to their creation and had an easy case of Kill and Replace, but the other way around wouldn't really work.
But it's still somewhat possible in V3. This theory claims that Team Danganronpa kidnaps people, creates their homunculi versions unbeknownst to them, likely returns the originals to society so as to avoid suspicion as even if they recall their kidnapping they probably don't have much information about the location, then overwrites the memories of the homunculi and uses them for their killing game. This explains how they were able to do it for so long without being caught.
Assuming Team Danganronpa actually only broadcasts the killing game only to themselves, this leaves no evidence aside from keeping defective homunculi somewhere in their hidden location. Perhaps Makoto Kagutsuchi or "Yuma" somehow found evidence of defective homunculi being stored there... And if Team Danganronpa really broadcasts the killing games to the public, the fact that there are people who are alive in the public, but students looking exactly like them died on the show likely caught the attention of this game's Makoto, who suspects they might be using killing homunculi for entertainment and has an understandable It's Personal reaction to it.
Thus, the sequel will be about investigating Team Danganronpa's crimes and putting an end to it once and for all, potentially with the help of V3's survivors.
