haha yep! it's a "feature". Not the best messaged feature/gameplay in the game but it's a sinkhole and when you roll over that part of the ground, it appears and starts to fade in so you gotta get outta there before the hole fully appears and you fall in. We'll add some sounds and better animation for this eventually, but yea, that's what it is for now. They become much more prevalent as you go up the mountain so good to know about for sure. :)