FIL Constantly Stares at Me

So every time I go over to his house since the first day I met him he just stares. I mean for the first year I thought he was just studying me and getting to know me and I appreciate eye contact so I didn't really mind and was fine with it. But the longer it went on the more intense the stare got and the more uncomfortable I've gotten. He does this squinty eye staring thing and its really creepy and it feels as if he is boring into my soul. I tried staring back at him during family dinner one night which everyone promptly noticed and it made everyone uncomfortable. He never faltered. My husband finally pulled me away. I asked my MIL about it and she's unsure and couldn't really figure out his obsession. I dropped it for awhile and I like the man okay he has never hurt me or raised his voice at me and even hugs me and treats me like his own daughter but I am so creeped out. I have some theories as to why he is doing it: 1. He is desperate for me to like him but he knows i like him and see him as a third father 2. He is zoning out but the dinner thing rules that out 3. He dislikes me but he treats me well so that can't be it 4. This last one I hope isn't true he has a crush on me and this creeps me out too much to even think about. I asked him once why he studied me so intensely and he just shrugged and said idk so I'm just confused. It's as if he's looking for something it he has found something and wants me to acknowledge it. I'm a very dominant person and many describe me as a person who is noticed by all as soon as I enter the room. I enjoy debate and challenges and I feel as if maybe he senses that. We go at it often not arguing but we do get in heated debates or simply full up a room with out personalities if that makes sense. Its as if we are dominant wolves fighting for pack leader its so strange. Lately I've been winning a lot of these clashes and he seems displeased with me. I never start it and have no desire to clash. I want to have a harmonious peaceful family but I can't just stay silent or be passive aggressive when I disagree with something or know something is morally wrong. Idk what to do. Why does he stare? What does he want? Why does he challenge me? Its all so bizarre. Please help.