The purpose of this guide is to show how to get the Hydroculus on the air, but we also get a Precious Chest so I’m just gonna change the topic to that.
Teleport to Weeping Willow’s southeast waypoint and head south. There are 3 hat jellyfish here and you need to complete their puzzles so the hat will move and create a line to launch yourself at the Hydroculus on top.
The puzzles are: (1) activate hydro monuments according to the number of Pinecone near them, (2) extinguish all the torches around the hat jellyfish, and (3) defeat enemies surrounding the hat.
This is the first one. You can see 4 Hydro monuments here, and all of them have a certain number of Pinecones around them. Activate the monuments according to the number of Pinecones they have (the solution is in the image above).
For the second hat jellyfish. Use Hydro to extinguish the fire on all torches around it.
For the last hat near the Shrine of Depth, just defeat the Pyro Slimes around it. After that, all 3 hat jellyfish will line up and you can use it to reach the Hydroculus in the air.
A Precious Chest will also spawn on top of a waterplank.