SPOILER ALERT!!! Hey, guys. There is, like, a big mouth with spooky teeth in the new little cave under the lake. Use scooba mask, special little oxygen tank for it that you can all buy from the shop (but they are quite expensive). Look in the "Info" option in the Player's Inventory (once those items arrive) for those items to understand how it works and whatever... Go to there with the scooba mask equipped. Dive in to there. Once you are there, you'll see it. I don't know what to do to it to give your Kurfus Omega back. Bring explosive barrels, fuel canisters or throw molotovs at it (I don't know, it might help). Just save the game and try it. Personally, I never encountered this event. I'm still, like, on the day 22-23... Earlier this day, @XanerGrono wrote that his Kurfus Omega disappeared near the lake so... Well, connect the dots.