In the Pratchett's book The Amazing Maurice and His Educated Rodents, there is a moment when
rat king causes that
the intelligent cat Maurice
lose his intelligence and attacks the albino rat Dangerous Beans. Maurice dies, meets Death and loses two lives (one for himself and one for Dangerous Beans).
After that, Maurice wakes up and
is intelligent again.
How is that possible? I think it is not explained in the book at all.