Below is a walkthrough for the Legendary Bow side quest in Tiny Tina’s Wonderlands. To obtain this side quest, speak with Raela in the Overlands after blowing up the ocean.
Pick up scroll
Retrieve the scroll in the north.
Reach cave
Once you enter the cave, complete both back to back encounters then retrieve the Legendary Bowtie from the chest. Afterwards, leave via the portal.
Return to Raela
Head back to Raela on the hill in front of you and speak with her to complete the quest.