<human>: Can you condense the text into a few key points?

Let's keep it short. My friend "Mark" had been good friends with me for 3 years. During the summer we'd hang out nearly everyday and during the school year we'd keep in touch. He's always been kind of volatile, ranging from really clingy and friendly to cold and kind of mean-spirited. I never really cared because I chalked it up to him being my "sassy gay friend" and just saw this as part of his personality. 

However, this past summer (2014), he started to be really cold towards me. He invited me out once during the summer to go swimming with him and some friends at our favorite swimming hole and he pretty much ignored me the entire time. That's the only time he asked me to hang out that summer. All the other times I saw him was due to our mutual friends and he also pretty much ignored me during those times as well. During the school year, I messaged him about 3 times trying to catch up and each time he "saw" it and ignored it. At that point, I was so fed up with him that I blocked him on facebook and deleted his contact. I didn't give him any explanation, I just did it. He never tried to contact me. I never understood what made him turn, but again I accept that he is a volatile individual and sort of manipulative, so I don't think it was anything that I did. 

Now, a good and mutual friend of ours is in town and I've heard through him that Mark wants us to all hang out like old times, but I'm not so sure that I want to give in to that. I feel like if I agreed to hang out with him, he'd see this as me accepting his shitty behavior.

Should I just keep on with him out of my life? Should I have a conversation with him about how his behavior made me feel? Or am I overreacting and should I sweep it under the rug?
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<bot>: Used-to-be friend who gave me the cold shoulder for a year is now asking to hang out again. What do?