This is just a hunch, and people more familiar with newcomer behavior might be better qualified to judge this:
User "Mike Song" joined today and already wrote answers to a number of pretty old posts. These answers somehow smell of being generated by LLMs, although I would not be able to pinpoint exactly what makes me suspicious about them (maybe the perfect spelling is an indicator). What do others think? Just a prolific and interested writer? Or really a bot user (although I would have no idea why one would want to do that)?