The challenge dungeons have some of the worst bosses in the mod depending on which one you do.
Royal Guardian Tier 6 Dungeon[]
This dungeon found in the Unstable Dimension is a tier 6 dungeon. The dungeon contains dangerous levels of mobs, a prince spawn egg, full Royal Guardian Armor and a Royal Guardian Sword. This dungeon is extremely difficult and has formidable bosses. Should not be taken on unless you are prepared.
Queen Scale Dungeon[]
Although this dungeon is similar to the Royal Guardian Dungeon but more dangerous as they contain different mobs that are stronger then a Royal Guardian Dungeon. They contain full Queen Scale Armor, a princess spawn egg and a Royal Guardian Sword. They however, do not contain a Queen Scale Battle Axe.