Below is a walkthrough for the Lens of the Deceiver side quest in Tiny Tina’s Wonderlands. To obtain this quest, speak with Margravine after completing the Wargtooth Shallows main story.
Go to ruins
Head north to the objective then enter the ruins to begin an encounter. After you defeat all the enemies, jump through the portal to another encounter. Complete this one as well then loot the item from the chest.
Talk to Margravine
Return to Margravine and speak with her
Take Magical Telescope
Grab the telescope from Margravine.
Cross hidden Coiled bridge
Follow the objective to the bridge and cross it to complete the quest.