I know from experience that sound means defeat

You had Triple Inkstrike as your special :

Whats the best special for the boss?

Mostly, in my opinion, it could be Triple Inkstrike and Booyah Bomb, but it could be anything else, since that's my opinion and my opinions aren't facts-

i mean you do get a free special again

they always give you one after you super jump!

I have had this MANY times before. Cost me a Superprize once.

Been there

They always put you at one special for cohozuna