Right next to Kastellholmen lies an old wreck that previously was believed to be the Danish warship Graa Ulv, or The Gray Wolf. Built in 1642, it was captured by the Swedes in the battle of Ebeltoft[a] July 23rd, 1659, and then served in the Swedish navy under the name Grå Ulven until 1668. It was at some later time sunk and filled with stone to serve as the foundations of a bridge between Kastellholmen and Skeppsholmen.
But when the water level in Saltsjön drops enough, the gray wolf rises above the surface. This has happened in 2009, 2013, and now in 2026.
New investigations into the wreck indicate that it most likely isn't Graa Ulv, and further investigations would be required to accurately identify the wreck. Given that these two islets have a long history of shipbuilding, the water around them can best be described as a graveyard for ships where wrecks are all over the place.
Still, until it is identified, I'm not giving up on a name that gives me a nice article title.