Dungeon Demon

The Dungeon Demon is an Exetreme Mode boss that appears when trying to enter the dungeon after the Moon Lord is defeated. It must be defeated to enter the re-vamped dungeon

Summoning
When trying to enter the dungeon in Exetreme Mode before the Dungeon Demon is defeated, you will be pulled back and a message pops up saying "An evil aura fills your heart..." You will have two minutes to prepare and then the Dungeon Demon spawns.

Phase 1
During phase 1, the Dungeon Demon attacks by teleporting onto you and hitting you and throwing Possessed Swords which inflict Distortion which will confuse the player. It teleports around frequently so a homing weapon is reccomended.

Phase 2
At half health, the Dungeon Demon enters phase 2. It will start shooting Cursed Flames which are fatal and Possessed Swords become stronger. In expert mode, it charges up a Waterbolt Fury for 5 seconds every now and then which unleashes a wave of Waterbolts, instantly destroying an unprepared player.

Aftermath
After the boss is defeated, it will unlock the dungeon again and drop 40 gold coins. The Mask and Trophy are not garunteed, but you can summon more with the Mechanic Voodoo Doll which all Dungeon Mobs drop in Exetreme Mode.

Trivia

 * This is one of few bosses which can be fought during the day.