Phantasm Dragon

The Phantasm Dragon is a flying enemy that spawns during the Lunatic Cultist boss encounter. 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.

Tips
If you have already defeated the lunar event, you can use the Solar Eruption to easily kill the phantasm dragon

Trivia
In game, the Phantasm Dragon seems to have more legs than Wyvern.

History
Dragon Fantasmique