RW - when my little brother was 3 he had a habit of sticking things up his nose and he stuck a rock up there one day and it didn't come back. He told my mom but of course she didn't believe him at first.
Fast forward 4 or 5 years and he's having all kinds of sinus issues - infections, nosebleeds for no reason, etc... So the docs eventually do an X-ray and lo and behold, there's this foreign object stuck in his upper nasal passage, messing everything up.
A nasty surgery later and he had himself this little rock souvenir to remind him not to stick sht up his nose anymore...
Sig courtesy of Soty - muchos gracias amigo!