Block 666666 has been mined by BTC.com.
INSIDE the mined block was a transaction with hash 057954bb28527ff9c7701c6fd2b7f770163718ded09745da56cc95e7606afe99 which included that message.
Block:
https://blockchair.com/bitcoin/transactions?q=block_id(666666)&s=id(asc)#
Transaction:
https://blockchair.com/bitcoin/transaction/057954bb28527ff9c7701c6fd2b7f770163718ded09745da56cc95e7606afe99