As Batsy is on the way, Big Blue bellows loudly. This seems to surprise Batsy, because he does not resist in the least (natural 1 Fort save), and takes 10 points of sonic damage and is deafened, which means no blindsense until his hearing comes back. Batsy has 17 HP remaining. Batsy is so rattled that he forgot to bite, bouncing off of Big Blue's hide (rolled 15+2(charge)-2(shaken)=15).
Round 464: Big Blue steps to 10N40E and bites and stomps wildly, hitting with bite (rolled 26) for 10. Batsy has 7 HP remaining.