Hi I'm new (and not a mother tongue) so forgive me if I'm doing something wrong with the reply, but I don't think I've seen the theory - many people think it's true - that says Tyrion will die in the end from a belated form of greyscale killing him from inside out, turning into a gargoyle and so fullfilling both the prediction that his mouth will be his end and the dream he had in ACOK:
The key points of the theory are:
1- Twyin, Varis and Tyrion himself always said he'll die because of his inability to keep his mouth shut.
2 - when he swallows black water (potentially getting greyscale), it happens like that:
3- back in ACOK, he had a dream where he was experiecing exactly the same that happens to people who suffer from greyscale
4- greyscale can be silent for a long period of time and start from inside, so one can't tell he's ill
5- Tyrion is constantly compared to gargoyles (as Shireen, who suffered from greyscale also was), so that he might literally turn into stone (because he didn't just get touched, he swallowed half the river) and so literally become stone resembling a little gargoyle
I have to say if this Tyrion's endgame I'm going to ask for my money back, but it seems pretty likely unless it's misdirection.