Kelpwillow

Kelpwillow is a coral ancient located in Nazjatar. To wake up this ancient, obtain a Prismatic Crystal (item) that are found near waterfalls, find and charm a Muck Slug with the crystal then head towards the ancient with the slug.

Drops

 * Ancient Reefwalker Bark (item)
 * Azerite
 * Prismatic Manapearl

Objective of

 * Bounty: A Few Coral Ancients
 * Bounty: More Coral Ancients
 * I Thought You Said They'd Be Rare?