Blue Ocean is the third stage in Sea of Tuna.
Attacking the Base
After the base takes a few hits, the enemy's castle will spawn 5 Otta-smack-u's and will continue to spawn them at a faster rate.
Begin the battle, save money for Bahamut Cat, Kang Roo and Otta-smack-u will instantly die after the attack. After that, spawn non-stop Wall Cat, Sexy Legs Cat, Dragon Cat, Valkyrie Cat and Bahamut Cat.