I'm not sure what kind of experience you've had with it, but I've use it for ferrets and rats. I'm just basing this from my own personal experience, so it could be different from someone else.
Anyway, I haven't seen this with just plain urine in the ferret litter box. But I've seen these pellets expand roughly 3-4x the size without breaking down when the rats spilled water and flooded their cage.
In regards to the snake, Kitedemon has mentioned snakes getting blockages from paper towel. And as hair/fur is indigestible, I just assume some certain things aren't either. It could be very well that a snake can digest an expanded pellet. But I'd rather not risk it personally.
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