Besides the Rune Switch explained earlier, youβll also need to find and complete the Tiny TinaβsΒ WonderlandsΒ Sunfang Oasis Ancient ObeliskΒ challenge if you wish to get 100% completion in the Sandy Sanctuary area. The Ancient ObeliskΒ is relatively easy to find and accessible even if you approach it while playing the video game on a higher difficulty level.
Where To Find the Sunfang Oasis Obelisk
The map below shows the location of the Ancient Obelisk in Sunfang Oasis, and as you can see, itβs inside a cave on the southwestern side of Aorta Lagoons.

This cave can be accessed when you enter Sunfang Oasis, meaning that you donβt have to complete any of the side-quests to get to the Ancient Obelisk. As you descend toward the location I have marked above, youβll see the obelisk in the center of the cave, and this is the area where youβll have to deal with another mini-boss, known as Oculus.

How To Complete the Ancient Obelisk Sunfang Oasis Challenge
Before activating the Ancient Obelisk, it is worth knowing that youβll have to deal with many Coiled mobs. These enemies are very weak to ice damage, so try using the proper spells and weapons. You should also know that most Coiled in the arena are resilient against poison, which means that youβll likely deal less damage.
Last but not least, since the arena is in a cave, if you donβt want to get surrounded by enemies, you can retrace your steps to the tunnel at the entrance. This will force the enemies to line up in front of you. The Oculus boss is a Cyclops that spawns only when the Ancient Obelisk is charged.

Like the Coiled mobs, Oculus is very weak to ice, so you donβt have to change your weapons, but youβll want to stay mobile because it can hit hard. Finally, donβt forget that after you defeat Oculus, youβll also have to shoot his flying eye.
If you manage to beat Oculus, youβll have a chance to get the Legendary Calamity Armor and the Perceiver Legendary Pistol; however, the drop rate depends on your Loot Luck. Consider looking for all Lucky Dice if you want to increase your characterβs Loot Luck.