Sexual Harassment or a joke?

Today was my first day working at a new job. So I was working and all of a sudden this guy comes up behind me and puts his chin on my shoulders and he said in my ear "are you available tonight? I answered "no I'm not." Then he said "hymm" and spanked my butt. Then he tried to pull up my shirt because he wanted to see if I had any abs. How should I take that?