Thanks for the comment. Thinking out loud, for prions is not the requirement that they "[act] as a catalyst, lowering the potential energy barrier ... to the po

Thanks for the comment. Thinking out loud, for prions is not the requirement that they "[act] as a catalyst, lowering the potential energy barrier ... to the point where e.g thermal fluctuations allow it to cross that barrier" also a guarantee against this type of ice-9 "infection" scenario, because the equilibrium of the environment itself would be so impacted and be absorbing that energy and then causing unfavorable conditions to the reaction at the reaction's frontier even? I more-or-less equate that to the "supercooled water + normal ice" reaction of how much energy delta you can create allows you to make a small energy explosion reaction/state-change/etc that isn't truly an "infection" but just a localized energy transfer. But okay, after stating this very interesting mechanism in that form, I see the point being made by others. This catalyst-style mechanism which can induce physical changes in the environment without itself changing could be exploited on scales that would allow one to "maliciously/adversarially" create a chemical / energized substance that would catalyze say a lake or an ocean into freezing / sublimating. However, I find it impossible to see how such a transition could be found for water though, and it seems to me the nature of the prion & proteins is that the prion requires some level of complexity in the matter it interacts with to cause this energy transition. For more exotic substances than water, or perhaps water which itself holds a large amount of solutes satisfying some characteristic, I could see it. I appreciate your insight into this matter clarifying the prion mechanism especially. I am also not well educated on these matters so hopefully it doesn't stink too bad :)