Why did this guy bully me and then all of sudden start being nice to me? is he gay?

So a few months ago, like back in March, this guy in one of my classes started making fun of me. I think he thinks I'm gay. He would say "Hey cutie" or "your lookin really cute today" or "whats wrong cutie?" when I ignored him. One time he also started feeling my arm and was like "Nice muscles". And I took it as him pointing out & teasing me that I dont really have any. He would also touch me alot like tickle my arm and stuff like that and smirk and act all innocent when i confronted him for bullying me. One time when he said "hi cutie" to me I asked him "Are you like gay?" & he surprised me w/ his response. he said "maybe"

Then, overnight it seemed, he stopped bullying me and started being nice to me. He would talk to me in a normal tone of voice, ask me about the sport that I play and make small talk , and sometimes give me compliments.. One time I was getting a drink @ the water fountain and he walked buy and was like "Hey Rumsy" and slapped my butt. I din't really think much of it at the time though because other guys at my school that I know, especially guys on my team, have slapped my butt before as a friendly gesture,im pretty sure.

But now I'm wondering, could he be a closeted gay and really just have a crush on me? He seems straight I would've never thought he was gay until he started this behavior. I know that sometimes people bully and/or tease the people they like...maybe hes insecure about his sexuality and taking it out on me?

WHAT DO YOU GUYS THINK?