December 2015 a Bitcointalk member discovered a puzzle transaction while playing around with his bot:
https://bitcointalk.org/index.php?topic=1306983.msg13381244#msg13381244
At that time nobody declared such a puzzle transaction which was created January 2015 until the creator of that competition came out 2 years later:
https://bitcointalk.org/index.php?topic=1306983.msg18765941#msg18765941
As of 01/10/2019 there are still more than 100 BTC to win. https://bitcointalk.org/index.php?topic=5166284.0

We think that the early mined coins of Satoshi are also a prize competition and that Satoshi is waiting this coins to be moved. We also think that he will not respond after somebody moves the first coins but it will be a message to the Bitcoin community that the private keys are somehow on the blockchain. If Satoshi disagreed with that conclusion he would have moved the coins to other addresses.

Re: Maybe Satoshi created the greatest prize competition https://bitcointalk.org/index.php?topic=5150688.0