The ultra marine appears in the same place as the loss leader in the Hinterquarters are the gem variant. Players can trigger the monster to appear at will by launching Erik or Mia up to a specific ledge with the loss leader in view and then rotating the camera until the ultra marine appears instead.
Etymology
Ultra marine is the term for the powdered form of lapis lazuli
Gallery
The ledge where either child must stand to rotate the camera and trigger the marine to appear