Easiest boss in the game with Ammo Baron.Simply use a shield and he can't touch you with his projectiles !
First you'll need to hit the 3 spots in his shell in the good order (it's random).And then simply hit his tail.If you had drunk a Monster Milk+ you can kill it in 1 try.Easy ^^
Here's my video guide to show you my pattern:
Good luck and have fun guys !
Don't hesitate to comment my guide if you want to get more infos