He mentions a party the same evening where we can meet but it sounds like a casual meeting so I don't really listen. The afternoon, I decide "hey, why not, let's see where it leads". I ask him on skype (yeah he's very social so half the people in a room have his skype) for the name of the place. He keeps me like 30 min on there to talk about the music he likes etc... It's interesting and fun and I decide to go to the party.
He seems very keen for me to come.

He arrives, comes to me and says hello with a nice smile and... completely ignores me.

One guy you seemed to fancy me a bit (too young) said "well you're trying but I can see that something is stressing you" (well I hope my former date didn't notice that I was laughing a bit too hard at some people's jokes).
I talked to him briefly about his job and this and that. He was almost aggressive towards me. He made even fun of me in a kind of cruel way at some point before catching himself.

When I said "let's call it just sex then" he protested loudly. Although all the many compliments he made in the beginning were all linked to sex or appearance. I know he liked my mind but he didn't make compliments about it.

What should I do now? We are in similar clubs and we go to the same events. 1) Should I stay away from all the events?
2) Go but don't talk to him at all,
3) Talk to him casually and pretend I don't notice his efforts at keeping me at a distance. Distance myself inside.
4) Write him a note explaining that I was glad we could talk again and tell him I know full well he's not into me and that's ok, we'll find someone else and explain that if the weirdness stays I'll just stop the contact?

3 has my preference although I wonder if the aggressive tone will go away. Yesterday he barely said goodbye. He demonstratively grumbled like he didn't give a ****.

Now he's in "I want to have fun", "Yeah, party time" modus. I have the feeling it's a new chapter in his life and not sure he's actually interested in any relationship.

I am tired of all this. We did have a lot in common but I don't think he ever was into me. I am distancing myself inside. Thankfully I never really believed he was interested.