I used to work at this office where the manager always used to give me a "thumbs up" for not licking our outgoing mail envelopes in order to seal them. She said she read a story about some random office worker getting a paper cut on her tongue from an envelope, and after some time, her tongue started swelling. It just kept growing, so when she went to see a doctor, they had to intervene surgically. Turned out some roach egg from an envelope got stuck in the papercut in her tongue, and a cockroach grew inside it; conveniently running out as soon as an incision was made on the tongue.
Could be lies; no idea.
Bullshit, for too many reasons to even list.