Everyone's heard of Erwin Schrodinger's famous thought experiment. You put
a cat in a box with a bottle of poison, which many people would suggest is
about as far as you need to go.
-- (Terry Pratchett, The Unadulterated Cat)

In fact, the mere act of opening the box will determine the state of the
cat, although in this case there were three determinate states the cat
could be in: these being Alive, Dead, and Bloody Furious.
-- Schrodinger's Moggy explained
(Terry Pratchett, Lords and Ladies)