Guy's Behavior

Shy Guy Behavior?

There was this guy that I met at a party. At first he was very outgoing and talkative to everyone, including me. He made make good eye contact whenever we spoke to each other. He would sometimes stare without me looking (it was obvious from my peripheral vision though). After him looking without me noticing, however, at one point during the party we wanted to play a game. We all had to sit physically close to each other. I was sitting near him and he just seemed quiet and off, not like before at all. I would sometimes crack jokes and the whole group would laugh except for him.. but when none of them laughed, he would be the only one who would laugh... loudly. I asked him a question about the game and he completely ignored me.. and when I asked him another question he mumbled and avoided eye contact (he looked down and obviously avoided my eyes despite the fact that he did not do that an hour ago). It was not like I was "all over him" and speaking to him only; it was a small party and so we all spoke to each other. He even mirrored me at one point too. I am just confused as to why he went from an outgoing guy to a quiet, awkward one?
Shy Guy Behavior?
Post Opinion