Blood Oil

Blood Oil is a Raw Material that can be found in the Blood Kelp Zone and Blood Kelp Caves biomes.

Pustules of Blood Oil can be found attached to the lower part of Blood Kelp stems or on Blood Cave Roots. It can be harvested by the player without any Tool. The PDA description notes that it is an oily goo.

It can also be spawned using the command "Spawn BloodOil".