Have you guys heard of user 'knightmb'? He owned 371,000 BTC at one point and maybe he still does.
If I remember correctly he was hired by people in Bitcoin's early stage to built a Bitcoin prepaid card or something like this for them. Then the project was abandoned and the people who hired him never bothered to check how much bitcoins were actually worth and knightmb convinced them to sell the 371,000BTC to him for $ 5,000.

Cheeky guy

He later claimed to have 'donated' them, but other users were able to disprove this claim.