stackoverflowin (@lmaostack) is a blackhat who in the 1st week of February 2017, hacked more than 150,000 printers, having them print various messages including the following:
"stackoverflowin the hacker god has returned, your printer is part of a flaming botnet, operating on putin’s forehead utilising BTI’s (break the internet) complete infrastructure."
"stackoverflowin has returned to his glory, your printer is part of a botnet, the god has returned, everyone likes a meme, fix your bullsh*t."
"stackoverflowin/stack the almighty, hacker god has returned to his throne, as the greatest memegod. Your printer is part of a flaming botnet."
According to stackoverflowin he is doing this to raise awareness about the pitiful state of printer security.