Capture crabs by whacking bushes until they appear and then grabbing them with your net. Once you've captured 40 crabs, talk to Otto the Geologist to proceed.

Quests - OoR

Zone Received In: The Underground River

Previous Quest: Mind the Gap

Requirement 1: Capture 40 Crabs (0/40)

Requirement 2: Talk to Dr. Otto

Reward: 300xp (!)

Next Quest: Mapping the Cavern

Questline: Journey into the Earth...

Note: Because this Quest re-appears later as a Daily, it's highly recommended not to continue to work on completing the puzzle or acquiring the custom item in the Map Zone when you complete this Quest.