I think you need to fold preflop - UTG has a very wide range but you're likely still a dog to it and the CO likely has a premium as he called 25% of his stack (choosing not to isolate) - I put him on a big a pair, AK, or AQ maybe. Based on my assumed range for the CO you're a big dog to this board. His 3600 looks to me to be bait - I fold.