Devin Oliver, a blond person that sings for I See Stars, made a cryptic reference that may signal a major plot development on next season of Game of Thrones. The singer posted an Instagram image of himself holding a bow with a caption that said he "may or may not have made an appearance in Game Of Thrones season 7."
His post got us thinking that we could soon see Rhaegar Targaryen. You might not recognize the name, but he is Jon Snow's real dad. Snow's parentage had been the subject of much online speculation that turned out to be right on the money. Rhaegar was essentially the last Targaryen to matter before Daenerys, his younger sister. He kidnapped Lyanna Stark, who was promised to Robert Baratheon, which kicked off the rebellion that led to Baratheon taking the Iron Throne. So he's kind of a major character, in that he got mega horny and started a giant war.
Or it's also possible, even likely, that we'll see the Mad King, Aerys Targaryen. He famously stored the Wildfire that Cersei used to commit domestic terrorism. He was also murdered by Jaime Lannister.
But, given Oliver's age, we could also meet Aegon Targaryen, Rhaegar's son, nephew to Daenerys, and half-brother to Jon Snow. He appears in the books disguised as a commoner, but eventually reveals himself as royalty. He, of course, makes his own claim to the Iron Throne.
Either way, Devin Oliver is a very talented person who was probably just making a joke about holding a bow and arrow during a music video.