Destiny 2’s Season of the Haunted began on May 24--bringing an Escalation Protocol-like activity and more to the Derelict Leviathan destination. The Leviathan is as massive as before, with multiple regions to explore--making it perfect for Easter egg hunts. Opulent, golden Bobbleheads of Cabal Emperor Calus are scattered around the ship. At the H.E.L.M. by the Crown of Sorrow, you can check which Bobbleheads you need for your dignified effigies of Calus display.
Collecting these progresses the #1 Fan triumph under the new Haunted Triumphs Seal for the Reaper title. Players must collect all Calus Bobbleheads and display them at the H.E.L.M. to get the Eidolon Exotic Ghost shell.
The Castellum Bobblehead is easy to find, but hard to get. After you land in the Castellum area of the Leviathan--which you can access from the Moon destination--head out of the hallway and turn to the left. There will be a small lever with red lights in front of a locked door with the Castellum Bobblehead inside. In order to unlock the door, you will need to clear Tier 3 Nightmare Containment--lifting the lockdown protocols.
When the protocol is lifted, head to the lever to unlock the door. The Bobblehead will be on the floor of the tiny room. The door closes after a few seconds so be sure to grab it in time.
You can tell if you have access to the door by the chest cache waypoint inside the room after the lockdown protocols are lifted. The two doors unlocked by the lockdown protocol are random, so if you can't open the door, you need to complete Tier 1 through Tier 3 Nightmare Containment again.
You can head down to Pleasure Gardens from the central doorway in the Castellum. Go to the front of the room where the giant statue is standing. This
Read more on gamespot.com