There is a treasure chest to be found in the Pond Depths in Grounded, and players must obtain the Mossy Key in order to open it. This key is quite well hidden, though, and some fans may struggle to locate it. Alternatively, players may encounter the Mossy Key before they have an understanding of where it is to be used. This guide is here to assist both groups of players by providing full details on Grounded's Mossy Key.
Updated July 13th, 2023 by Russ Boswell: Although Grounded has seen some recent updates, developers haven't changed much with the Mossy Key. Players looking to find the Mossy Key in Grounded can still snag it in the same location outlined in this guide. Unfortunately, that can be a bit easier said than done, as the key itself is hiding in a pretty dark and foreboding area. To better help players understand what they're getting into when they look for the Mossy Key in Grounded, as well as what it unlocks, the following guide has been updated.
Grounded: Mossy Key Location
Players that are on the hunt for the Mossy Key should begin by equipping a Bubble Helmet, Fin Flops, Spear, and Slime Lantern. These fans should then make their way to the position that is marked on the map below and dive into Grounded's Koi Pond, taking care to avoid any fish in the area. As players descend at this position, they will see a stream of bubbles rising from a tube that is below them, and they should follow that tube to reach the Sunken T-Rex.
From the Sunken T-Rex, players should swim northwest, passing by a series of columns and entering an area with wires, electrical panels, and lights. Fans should swim to the two cylindrical lights that are mounted to the wall at the far end of this area and look to the right. There is a small opening in the ground, which is covered with Algae, in this position, and Grounded players should enter, follow the tunnel to reach a chasm with tubing in it, and grab the Mossy Key that is on the ground near that tubing.
Unfortunately, the area that contains the Mossy Key is incredibly dark, and filled with Diving Bell Spiders. It can be a bit tricky to navigate, and players will have two options for reaching the key. They can either fight each Diving Bell Spider as they encounter them, which will make it easier to navigate the dark corridors, or they can simply try to swim past all the creatures and snag the key. It is possible to outswim the spiders using the Fin Flops, but it's easy to get lost in the low-visibility area, especially when being chased by a group of mobs.
Players may want to take a strong underwater weapon with them, like the Bone Trident. This weapon can be unlocked by analyzing a Diving Bell Spider chunk or a Sunken Bone and takes 3 x Silk Rope, 3 x Diving Bell Spider Chunk, and 3 x Sunken Bone to craft.
Gronded: Mossy Key Sunken Chest Location
After collecting the Mossy Key, players should make their way back to the Sunken T-Rex in the Koi Pond and again swim northwest toward the aforementioned columns. There is a chest on the ground near the root that is just past the first column, and indeed it is opened with the Mossy Key. For full clarity, the position of the chest has been marked on the following map, and there is a reward for survival game fans to claim inside the container.
With respect to the specifics of that reward, the chest holds the Sunken Outpost BURG.L Chip. This Auxiliary Chip in Grounded can be delivered to BURG.L back at the Oak Lab in order to unlock the Splatburst Recipe, the Fin Flops Upgrade, and the Slime Lantern Upgrade. These unlocks cost 2,500 Raw Science, 1,500 Raw Science, and 1,500 Raw Science respectively, and players should give some thought to which they want to purchase first.
The Splatburst can be a great alternative to the explosive Bratburst, as it allows players to stick the bomb to surfaces and enemies. The original Bratburst will roll freely when thrown, making it unpredictable and difficult to use at times. The Fin Flops upgrade will allow players to swim even faster, and the Slime Lanter upgrade will double the amount of time the Slime Lantern works before breaking.
Grounded is available for PC, Xbox One, and Xbox Series X.