The servers for Steam, Origin, Battle.net, and League of Legends were brought down temporarily overnight by apparent DDoS attacks that seem to be related to a swatting attack on an individual known for streaming games. All of those services appear to be working normally as of this writing.
A hacker group going by the handle DERP Trolling claimed responsibility for the Origin attack on Twitter, saying it used a "Ion Cannon" DDoS tool it's calling the "Gaben Laser Beam," after Valve founder Gabe Newell. DERP claimed responsibility for similar attacks on Battle.net, League of Legends, World of Tanks, EA.com, and more earlier this week. Meanwhile, a pair of Twitter users are claiming responsibility for last night's attack on Steam.
All of these efforts to take down various games and platforms seem to be related to a swatting attack directed at YouTube user PhantomL0rd. A thread on reddit lays out how those attacks advanced from targeting the games PhantomL0rd was playing (and monetizing through ads) to more personal harassment after his address and details were released online. In a recent stream, PhantomL0rd reported on being handcuffed after having police called to his address.