With the Mesa update, you get to unlock new badges that have strange requirements for fulfilling the achievement. The 24 Karat badge in PEAK has a very interesting objective, where you are required to offer a worthy sacrifice to the Kiln. There’s no further explanation on where the Kiln is located or the required item to be tossed into it. This guide will explain how to offer the Kiln a worthy sacrifice in PEAK.
24 Karat Gold Badge Guide in PEAK

Before we go any further with the guide, this badge is currently unobtainable, but still attemptable. The easiest way to get the 24K Badge is with mods or by changing the coding script of the game. To get the badge, make your way to the new Mesa biome. While exploring the biome, keep an eye out for a large crack on the boulders or floor within the desert; it should look something like the image above.

There is also an exit point that is found on a larger rock in the middle of the desert. Refer to the image above to know what the exit of the cave should look like. The spawn point for the entrance and exit is random, and might not appear in your current playthrough, but might appear in your next run. Also, there is a high chance that these points will be locked because of the bug for the badge, rendering you unable to enter and complete the achievement.
How to Enter the Tomb
However, using the right mods help in getting inside the Tomb through the exit instead of the main entrance. By disabling the boulders blocking the doorway, it is possible to enter through the exit point and fall through the floor to get to the Ancient Idol room.
Another way to get inside is to utilize the glitch near the exit boulder. If you press Sprint near the boulder while pressing the key to hold and put back your backpack repeatedly, your character will start to slide through the boulder walls to reach the inside.
Offer The Kiln A Worthy Sacrifice

Now that we know how to enter and exit the underground system, head inside the entrance and climb over the rocks blocking your path till you come across a large gap on the floor. The only way across is to climb the side walls and jump on the rocks, or use your Rope Cannon to get across. Head inside the new entryway to find the Ancient Idol right in the middle of the room. If you came in through the exit via glitching or mods, then you will directly fall though to the main area.

Pick up the Ancient Idol and add it to your backpack inventory, then exit through the ramp below your entry ramp. From here, head all the way to the Caldera map and enter the volcano. Keep going till you reach the Kiln, then make your way to the center of the lava pool. Toss in the Ancient Idol, then stop your current run. You should get the achievement once you reach the main lobby.
As your reward for obtaining the achievement, you get the new Bing Bong Hat. Check your character customization options to equip it.
24K Badge Bug
As mentioned earlier, changing the game’s script will unlock the achievement, but is a more tedious process. You need to check whether the lava within the Kiln is together or separated. If separated, then the achievement won’t unlock unless the statement that the lava is part of the Kiln is true. The only way to get this achievement for now is to wait for the bug fix from the devs before making any major changes by yourself.