If some people in 2020 believe that A) vikings existed in 2012 and B) they would still invade places, then I'd say let them get confused, they'll be confused by anything.
My immediate thought was some sort of Viking LARP that went wrong
There's been a number of reconstructions of viking ships[1], and some of them like e.g. this one [2] have been sailed, so that would have been an amusing possibility.