Hi TravelingLady! Sorry for the delayed response. Generally speaking 'Steve' is a smart guy, and has a lot of practice noticing signs of when he is getting to someone so with that being said he will exploit that fact if he notices it. I've said things in a multitude of different levels of aggression ranging from "I wish you wouldn't say stuff like that" all the way to "If you say something like that to me again we are going to have a problem" but nothing really affects him in the long term. He may stop for a day or two but he'll be right back at it like nothing was said given the correct fuel.

Attempting to change the subject is very difficult to do as it will only go two ways: It will work and we will move on, except his negative feelings from the previous conversation will move with it and he will try and bait something else out OR he will notice what I'm trying to do, take it as a sign of distress and weakness and push further knowing that he is getting to me.

The problem lies in the fact that he usually doesn't need direct fuel to attack me as we've known each other long enough that if he is dry for material he will bring something up from before.

For example if I try and talk (to the group) about an experience I had with a girl where I thought she was interested in me he will blurt out "Oh look Mr.Casanova over here thinks every girl he sees is interested in him, he's so full of himself!"

Another example: I like to think I have a pretty good memory, and given past opportunities to definitively prove it I'm usually pretty spot on. That being said if I ever misremember or don't remember something he will say things like "Oh look, Mr. elephant memory can't remember. I thought you said you had a perfect memory?" and other things to try and ridicule me.

Honestly as I type this it sounds sort of like jealousy or resentment, as arrogant as that sounds.
As for my friends basically everyone I've spoken to in one way or another agrees that his behavior is unacceptable. Some have grown callous of his behavior and have resorted to avoiding any and all conversations with conflicting opinions and will very often resort to the silent treatment (most effective for him) while others take a more aggressive stance and call him on his behavior which unfortunately has never ended positively in the short or long term.

Generally speaking though, most don't let his behavior go. I've been trying recently to just let what he says slide off but at the same time its difficult to be his punching bag without at least telling him off. I'm not sure if this is the right course of action or if more extreme options need to be taken (if this isn't deal-able) like not being his friend all together and just cutting ties.