The Strange teleorb is acquired during While Guthix Sleeps. Players can teleport themselves to Lucien's camp by operating it inside the room above Dark Squall's Room with a Law Rune and a Death rune in the inventory.
It is found inside Dark Squall's room on the southernmost desk by searching it.
Players can still use this orb to teleport to Lucien's camp after completing the quest. The Undead trolls that reside there can be slain in place for normal Trolls for a Troll slayer assignment.