How to get the Mossy Key (and what to do with it) in Grounded

The Mossy Key is one of the many items you can find without much explanation in Grounded. You might also find a chest that requires the Mossy Key and have no idea how to go about obtaining it.

Either way, finding the Mossy Key and using it is a worthwhile endeavor in Grounded that leads to some intriguing rewards. Unfortunately for players, the key is extremely difficult to find if you don’t know exactly what you’re looking for and the chest that takes the Mossy Key is also not in the easiest location. To see where to find both the Mossy Key and what chest it opens in Grounded, take a look at the guide below.

Finding the Mossy Key in Grounded

First and foremost, you need to locate the Mossy Key in Grounded. Even throughout all of the game’s recent updates, the key is still located in the same spot it’s always been in.

Before departing to find the key, you’ll need a few items to ensure you can survive the journey. First, you’ll want any and all equipment that allows you to swim and fend off underwater creatures. This includes the Bubble Helmet, Fin Flops, and the Spear. You might also want to take a light source with you as the Mossy Key’s location is extremely dark and murky.

Once you have all of the necessary equipment, head to the Koi Pond in Grounded. The Koi Pond is located directly behind the large Oak Tree, which can serve as a landmark to easily navigate to the pond. For reference, the Koi Pond is on the northern side of the map and is also home to the Pond Lab.

At the Koi Pond, jump in and try to avoid any aquatic life you might find down there. Keep swimming down to find a tube with bubbles pouring out of it, which you can follow along to eventually find the body of a T-Rex dinosaur. Swim past the T-Rex to the northwest until you reach a large well-lit area with wires all around it. Go through this area to find a tiny opening in the ground at the end of it, just under two large lights on the back wall. The hole is covered with green algae, so it might take a few minutes to find it. After swimming through the hole, you can snag the Mossy Key that’s sitting on the ground near a large tube.

Be careful in the Mossy Key’s area, though, as there are spiders all around you. You can choose to fight all of the spiders or simply swim past them to reach the Mossy Key and then head back out the same way you came in. This is where the Fin Flops really come in handy as they give you some extra speed. You also want to ensure you have a constant light source, especially when you’re trying to look for the key. If you decide to fight the spiders, you need a strong weapon, such as a Spear, Bone Trident, or something comparable.

Once you have the Mossy Key, head back out and you can now go to the chest where you can use it.

Using the Mossy Key in Grounded

The Mossy Key opens the Sunken Chest in Grounded, which is right near the sunken T-Rex dinosaur you swam past to get to the Mossy Key’s location. Go back to the T-Rex’s location in the Koi Pond and swim past it toward the northwest. Just past the T-Rex in this direction are some lit-up columns that form arches. Swim past the first arch and then look toward the ground; you can find the Sunken Chest in the ground right past the second arch.

When you’re near the chest, interact with it and you’ll get to use your Mossy Key to open it. The rewards inside the Sunken Chest are the Mega Milk Molar and the Sunken Outpost BURG.L Chip.

And that does it for the Mossy Key and Sunken Chest in Grounded. You can also check out our previous guide on how to get Red Ant Eggs.