Ice Poseidon is a former Runescape streamer on Twitch (now YouTube), known for his Jace-tier gamer humor, propensity towards getting fucked with, and his unusual reactions to things. He's shown up in so many "Song Request Trolling" compilations that nowadays people make entire ones just for him;
This is not the only thing Ice does on his streams though. One of the things that make him so famous is his habit of streaming out in public. Here he is being annoying at a McDonalds for an hour.
This behavior only increased with the launch of Twitch IRL. Here's some more videos;
He made international news after livestreaming on a plane like an idiot and getting swatted. As Kotaku mentioned he was actually permabanned on Twitch for this.
Of note is that Ice is accused of dealing drugs to people like Baked Alaska and Andy Warski, and he is possibly getting arrested for handcuffing some pshyco thottie and staling her iPad.