A relatively recent rumour about the 4 things below was “created” by a very popular book. What’s the rumour?

(Will be modded on the 22nd)

Cracked by: rohanquizzer, KK, Anonymous, Sumanth Patlolla, Rogi, jowens, Bharath, Vishwas B Sharma, akhi, rickde, Manish Achuth, tsmyelin, badideabear and shrik