He Calls Me His Best Friend. What Does He Mean?

Ok do my guy friend let's just call him LAA cause those r his initials. Anyway every day at school he will come up to me and say your my best friend in this weird voice. I say uh ok I can live with that and he says just kidding. I have to hear him say it every day and sometimes he doesn't say jk he just says "best friends" in a low creepy whisper voice. LAA isn't really close. We have gone to the movies together like once and I c him at the park a lot but we r not that close. (I alsO helped him with his science project last year) I am super confused about what LAA means and when I ask him y he says that he tells me "cause u r my best friend" and I know I am not. If this helps: he is a clown (he always makes me laugh and cracks jokes), he is annoying sometimes, he has ok grades (no F's or D's), and he is Hispanic. BTW he hangs out with lots of girls but he has never said they were his best friend so I can't ask them what he means. Thx a lot!!