Thats the thing, in order to make them look like regular coins you'll need a way to add them to the chain. I'll be happy if experts say all is good with the blockchain system and those huge transactions are surely no hacks but due to the recent price drops and blockchain developments, interests in this technology the price fall is kind of paradox so looking at those transactions made me think if all is in order.
The address came from ViaBTC mining pool.
It is a null data transaction. Data was embedded in the blockchain. What's important is to utilize other block explorer before sowing doubt and confusion. The 12 BTC was obviously a block reward since it is a mining pool. Blockchain.info or soon to be Blockchain.com is not the only block explorer around for your information. Two outputs were created the other one doesn't contain anything since it is embedded data but blockchain.info is being used to create more doubt even though it is imperative that you should know something about embedding data in the blockchain.
Even walletexplorer.com knew that the error message from blockchain.info is not an address. Stupidity is being spread by stupid people.