Shoal of the Winter Harmony

"The vengeance of Harmony Shoal is known and feared throughout the five star systems!"

The Shoal of Winter Harmony are multi-nucleate organisms, functioning as an infinitely adaptable, independently functioning, peripatetic central nervous system. If you don’t speak Doctor, ‘body-snatching brains’ might mean more to you. They take over the bodies of humanoids by removing the brains and taking up residence, with only a faint diagonal slash across the host’s face as a tell-tale sign.

The Twelfth Doctor first encountered the Harmony Shoal in the 2010s when he foiled their plan to invade Earth by crashing a spaceship into New York. At some point in their history, the Shoal of Winter Harmony were conquered by King Hydroflax. Their reverence for the King lead them to the year 5343 where they tried to buy the Halassi Androvar, the most valuable diamond in the universe, from River Song. Little did they know, the precious stone was embedded in Hydroflax’s now-decapitated head which River had hidden in a duffel bag!