Flying Dutchman

The Flying Dutchman is a Hardmode mini-boss that spawns during the Pirate Invasion event. It has four cannons that drop cannonballs, and it will occasionally spawn standard Pirate Invasion enemies. The Flying Dutchman does not disappear after the Pirate Invasion is over (though it will explode if it has not been engaged before the invasion ends), and defeating the Flying Dutchman will not end the invasion. The Flying Dutchman can only be defeated by destroying all four cannons. Several Flying Dutchmen can appear during a single Pirate Invasion, or none at all. They only appear when the event progress has passed 50%, and where there is at least 40 * 40 space.

Tips

 * They can be easily killed with a minecart and a sufficiently long track, with the cannonballs only hitting the player if they slow or stop. This makes them fairly easy if you have a decent ranged weapon.
 * Due to the way it moves, and the way the cannonballs fire, it is very easy to find positions where it cannot hit you, yet you can hit it.
 * Due to the fact that they stop upon hitting a wall, and continuously spawn enemies pertaining to the pirate invasion, the Flying Dutchman can be stopped above a half block deep pit of lava (or other trap) and used to farm the various items pertaining to the pirate invasion.
 * The Meteor Staff can be great against the Flying Dutchman due to the meteor projectiles falling from the sky. If the Flying Dutchman stops at a wall, you can climb on top of the wall and fire the staff at the cannons without needing to jump over the Dutchman to attack it, thus activating the cannons. This technique will probably require Mana Potions, so if you don't have enough time to grab a few, a backup weapon would be good to use until your mana recharges.
 * The Daedalus Stormbow is also a wise weapon choice. When using it, the player simply must hold their cursor over the cannons, and eventually, the Flying Dutchman will explode. It is advised to do this from within a building, because the Pirates can easily kill an exposed player.
 * If you have a wall in the sky, say to find a sky island, if you go on the other side of the wall from the Flying Dutchman, a Flying Knife or the previously mentioned Meteor Staff can be very effective due to the Flying Dutchman's lack of ability to go through solid blocks (The Flying Knife if there is a hole in the wall).
 * If the player moves too far from the Flying Dutchman, instead of despawning, it will be destroyed, giving usual item drops and adds to the progress for completing the event.
 * Any weapons that can hit multiple targets at once are good for taking out the cannons.
 * Farming Lucky Coin/Discount Card/Coin Ring is most efficient from Flying Dutchman, rather than from common pirates. After getting event progress to 50%, you can ensure 10 Flying Dutchmen per event by getting high enough above ground (using small platform or flying mount), but not too high, so that spawned enemies will be in "Active Rectangle" and will despawn after 12.5 seconds, and then spawn again. Until Flying Dutchman eventually (usually it takes a short time) will spawn. After killing him, repeat the process till event ends. Parrots could reach you this way too, but you can kill them safely, they do not count towards event progress.
 * Being in a house/box and using a summon can also help during this battle, as long as your summon can fly/is a projectile user, you will be safe from the cannon balls, parrots, AND pirates but damage all of them safely. It must be noted that in order for this tactic to work, you must block up your door from pirates.

Trivia

 * During the 17th century, the Flying Dutchman was a mythical ghost ship that would float above the ocean. Seeing the Flying Dutchman was regarded as an omen of doom.
 * The Flying Dutchman is one of the only enemies in the game to have a special death animation (the others being the Moon Lord and Celestial Towers.) This makes it the only non-Celestial event enemy to have a special death animation. When the Flying Dutchman dies, the sail rips to shreds and gently floats down.

History
Hollandais volant 荷兰飞盗船