The underworld terror would be a hardmode worm boss that is damaged upon the attacking its crystals. Hitting it anywhere else heals him. Summoning To summon him you would need the magmatic flute,to make that need 20 hallowed bars, 5 hellstone bars and 10 of each mechanical soul. It is made at a mythril anvil and has unlimited uses. It can only be spawned in the underworld Stats and style It has 140000/180000 max health, 100/400 head damage, 50/200 body damage,15/125 tail damage, no head defence and 20 body and tail defence. It's style is similar to the destroyer, but you must destroy the crystals to kill it. Destroying all the crystals defeats the boss. In expert mode it releases flames upon destruction Loot Expert mode: Molten guard: 5 defence A molten crystal rotates around, denying all damage that hits it 25-60: Fire plates: can make some armour, some weapons and accessories Magma runners: infinite lava waders. Plates make: Magmatic Armor: 15 plates each piece Defence: 15, 24, 12 Set bonus: inflicts flames on attack Furious stabber: stronger Arkhalis with a projectile.