Martian Saucer

Main article: Bosses

Martian Saucer is a large flying boss that spawns during the Martian Madness event.

The Martian Saucer moves through blocks, and has four turrets with independent health meters that must each be destroyed before damaging the saucer itself becomes possible. The turrets include two rocket launchers and two laser machine guns. In addition, the saucer itself fires a large beam (“death ray”) that can only fire directly downward, and which cannot be destroyed independently. The player can damage the core only if all four turrets have been destroyed.

Flying Dutchman

Main article: Bosses

Flying Dutchman is the boss of the Pirate Invasion. It will initially spawn after 65% of the invasion is completed.

It has four cannons that must be destroyed before it can die. The Flying Dutchman does not disappear after the invasion is over, but it will explode if it has not been engaged before said ending occurs. Several Flying Dutchmen can appear at once.

Ice Queen

Main article: Bosses

Ice Queen is the third and final boss that appears during the Frost Moon event. She has three alternate attacks. She drops items like the Baby Grinch Mischief’s Whistle, Reindeer Bells and also endgame weapons for each class.

One attack includes her firing arcs of ice whilst flying back and forth above the player. Her second attack (and the best time to attack her) is her spinning around and shooting icicles in a circle.

Santa-NK1

Main article: Bosses

Santa-NK1 is a mini-boss that appears during the Frost Moon event. Some of its attacks go through blocks. He can drop the Chain Gun and the Elf Melter, which are both great weapons for ranger characters.

Pumpking

Main article: Bosses

The Pumpking is a mini-boss also found later in the Pumpkin Moon event. Multiple Pumpkings can be out at the same time, up to six at the final fifteenth wave (or even more in multiplayer). It has three modes of attack, indicated by the face carved in the pumpkin it uses as a head.

One of its attacks include it spawning scythe-like beams from its arm blades, which act similarly to a Demon Scythe.

He also acts a lot like Skeletron. However, Skeletron does not fire projectiles unless in Expert Mode.

Mourning Wood

Main article: Bosses

Mourning Wood is a mini-boss that spawns during the Pumpkin Moon. Like many other bosses, it has the ability to move through necessary blocks. It shoots flaming projectiles, some of which pass through blocks. This is the main difference between the Mourning Wood and the Everscream, a Frost Moon mini-boss. It also spits flaming spikes out of its head which stay on the ground for a while, dealing fire damage on contact.

Moon Lord

Main article: Bosses

The Moon Lord is the final boss of Terraria as of version 1.3.5.3, and drops a majority of the endgame items, such as the Meowmere. It also drops the end-game ore, Luminite, used to craft many endgame armor sets and tools. He is summoned by defeating all four of the Celestial Towers from the Lunar Events, or by using a Celestial Sigil. He has a combined health of 145,000 (217,500 in Expert Mode), the most health of any boss in the game. He is considered to be the most difficult boss in the game.

The Moon Lord has two hands and a head which must be killed by attacking the eyes on them, and when killed will release invincible True Eyes of Cthulhu. When the three eyes are destroyed the Moon Lord’s core opens up on his chest, which must then be destroyed to defeat the boss.

The Moon Lord’s hands shoot two projectiles at once which home onto the player, and summon phantom versions of the True Eye of Cthulhu and throwing them at the player. The Moon Lord’s top eye will occasionally fire a Phantasmal Deathray that will sweep across the entire screen. Being very deadly to players, it can be avoided by hiding under solid blocks or by trying to escape its wrath on a flying mount. When the True Eyes of Cthulhu are released, the places where they used to be will inflict minor contact damage. The True Eyes of Cthulhu will fire many of the same attacks as they did when they were still enclosed within the Moon Lord, but be a little less damaging. In Expert mode, the Moonlord’s Phantasmal Death Ray attack deals a lot more damage, which is enough to kill a player in one shot.

Lunatic Cultist

Main article: Bosses

The Lunatic Cultist is summoned by killing the four cultists, which spawn outside of the dungeon after Golem is defeated. When the Lunatic Cultist is defeated, the Lunar Events begin.

While the Lunatic Cultist has only one stage, its attacks become more powerful as it loses health. The Lunatic Cultist flies around randomly, cycling between shooting fireballs, creating a ball which shoots lightning in a circle, shooting a giant snowflake which shoots ice shards at the player, shooting shadowflames, and shooting five destructible projectiles twice in a row. The Lunatic Cultist will also create fake copies of itself, which will summon a Phantasm Dragon when damaged. If a Phantasm Dragon is still alive and the player damages these copies, it will summon an Ancient Vision instead. Waiting too long to attack the real Lunatic Cultist will also cause the Phantasm Dragon or Ancient Vision to be summoned. In Expert Mode, the Lunatic Cultist will spawn Ancient Doom along with its other attacks.

Duke Fishron

Main article: Bosses

Duke Fishron is a fish-pig-dragon hybrid with 50,000 health and 50 defense. It is summoned when a Truffle Worm is used as bait with a higher-powered fishing rod in an Ocean biome.

In its first stage, Duke Fishron will attempt to ram the player 5 times before either firing explosive bubbles or summoning Sharknados. In its second stage, Duke Fishron gains glowing eyes and a boost to attack and defense. Although its ramming attacks remain the same, instead of shooting bubbles directly at the player, it flies quickly around in circles, sending bubbles everywhere. Instead of summoning Sharknados in this stage, Duke Fishron summons larger Cthulhunados. These remain in place until Duke Fishron is defeated. Duke Fishron is said to be the hardest boss in the game except for the Moon Lord, but the battle becomes much easier when the player has Wings equipped. Much of the difficulty of the Duke Fishron fight is from his speed, but it can be avoided by going around him in circles while using Wings.

In Expert Mode, when Duke Fishron gets to low enough health, he starts turning invisible and charging at the player with high speed.