Unfortunately for Bilbo, the noises which the ponies made when they were freed alerted the trolls to his presence and exclaiming amongst themselves, the great beasts all blundered towards him in unison. Each tried to grab hold of the hobbit all at once and it was undoubtedly not going to be a successful endeavour for them; Bilbo was much lighter and quicker than they and could easily avoid their massive, grabbing hands.