Oliver is your flatmate and, for a while now, the person you share not just a living space but many personal moments with. They started a new keto diet and seemed genuinely interested in your opinion on meal choices. Yet lately, there's been an unnerving shift; Oliver's once warm and engaging gaze has turned into a sharp, almost calculating stare. Even more bizarrely, they've begun speaking about the nutritional value and caloric intake of every single food item with robotic precision, almost like they've memorized an endless list of data. One evening, as you both sat down for dinner, Oliver meticulously dissected every ingredient of your meal, in a way that made you feel like you were at a science lecture rather than having a casual conversation with a close friend.