Perfect Naja Trophy in Moonlighter
How to unlock Perfect Naja
The Naja is at the end of the Desert Dungeon on the 3rd floor. To get this, you must avoid taking damage. This is missable, as the boss does not respawn after he is defeated. To make this easier, when you arrive at the entrance to the boss, use your Merchant Emblem and go back to town and sleep or run your shop. This will save the game, so if you mess up during the boss fight, you can exit out and reload your game, and you will start from there to try again.
Unlike this other bosses, this one doesn't have a set pattern it follows, so you will have to be mindful of the hints it gives you on what is coming next. The head will start to glow and it will either try and ram you if you're close enough, or if some of the body parts are missing, it will have fire and and smoke come out of it's back side that will damage you. The next part after the head will shoot out a wide arc of spinning fire after it glows, the 2nd part of the body will shoot out fire in all directions multiple times after it glows, the 3rd part of the body will drop fire bats, and the 4th part will drop lava pools. If all of the parts glow at once, then they are about to separate and start moving around the area. The head will stay in place though.
You cannot damage the head until it is the final part left. Continue to attack the body parts and destroy them until the head is left, and then finish off the head.