Phantasm Dragon

The Phantasm Dragon is a Hardmode, post-Golem boss servant that spawns during the Lunatic Cultist boss fight. Its behavior is nearly identical to the Wyvern, and has very similar stats to it as well. The Lunatic Cultist summons a Phantasm Dragon each time the player attacks one of the Lunatic's duplicates. If the Lunatic Cultist completes the spell once more with a Phantasm Dragon still alive, it will summon an Ancient Vision instead.

Tips

 * If you have already defeated the Solar Pillar at least once, you can craft a Solar Eruption to easily kill the Phantasm Dragon since the weapon can hit all of the Dragon's 30 parts simultaneously, increasing the damage inflicted dramatically. This trick can be used with any Pierce or AoE weapon.
 * If the Phantasm Dragon spawns during the Lunatic Cultist fight, attack it with Vampire Knives, as the Phantasm Dragon is a very large target making the knives easy to land, which will restore a lot of health.
 * If you did not bring any AoE or Pierce weapons to the fight and you're confident with your aim, you should try to hit the head since it has 50% less defense compared to his bodyparts. Same goes for lingering AoE effect Weapons such as the Electrosphere Launcher or the Toxic Flask, as the Phantasm Dragon will first take extra damage from hitting it's head, then it's entire body has to go through the lingering AoE effect.

Trivia

 * The Phantasm Dragon is a total of 30 segments long. Its first segment being the head, the other 29 segments consist of the legs every four segments (for a total of 6 legs), with the final three being the tail.

History
Dragon Fantasmique