The Norse God of mischief. Also the villain in the movie "The Avengers" played by Tom Hiddleson that has completely taken over Tumblr as a whole and has turned previous fangirls of other media into Loki-serving mindless slaves.
Also another word for "troll" due to said event.
"You just got Loki'd."
"He's just Loki'ing, ignore him."
"That guy is such a Loki."