The Bloodworm is a critter found within the Sulphurous Sea after Polterghast has been defeated. The Bloodworm acts identically to a Truffle Worm, fleeing from the player if they startle it. Bloodworms can be caught with a Bug Net or Golden Bug Net. Using a Bloodworm as bait in the Sulphurous Sea will summon The Old Duke. Bloodworms will not spawn if the Acid Rain event is currently ongoing.
It can be purchased from the Sea King for 8 after The Old Duke has been defeated.
- The bait power's usage of the number 4 is a reference to the Chinese superstition about the mentioned number, due to it being a homonym for "death".
- Previously, the item's bait power was 69420%, a reference to the 69420 Nice memes.
- If the player attempts to summon The Old Duke using a multi-lined hook, such as the Early Bloom Rod, it will lead to multiple Old Dukes spawning in at once.
- This is an homage to an oversight in Vanilla Terraria, where multiple Duke Fishrons can be summoned using a fishing exploit.
- Similarly to the Truffle Worm, the Fisherman's Pocket Guide (and its combined accessories) will display a player's fishing power simply as "Warning!", due to the fact that The Old Duke will spawn when using this as bait in the Sulphurous Sea biome and no fish will be caught when not in the Sulphurous Sea biome.