On Sunday, season 7 of HBO’s Game Of Thrones wrapped up, drawing 12.1 million viewers live and a total of 16.5 million viewers if you include online streaming services—a record for the already immensely popular fantasy series. We won’t get too into the details of what went down, but we will mention that while many viewers were wrapped up in the various movements of the key players in Westeros and beyond, two players of a different type made a cameo in the season finale. In “The Dragon and the Wolf,” guitarist and singer Brent Hinds and guitarist Bill Kelliher from Mastodon, the Atlanta-based metal band, appeared as wights under the Night King’s rule, making for a special appearance that might have flown under the radar for many. This appearance was not completely out of left field, however. It turns out that the show’s co-creator and showrunner, D.B. Weiss, is a big Mastodon fan, and members from the band have previously appeared on Game of Thrones during season five as members of the Wildling army.