The Bone Javelin is a consumableranged / throwing weapon crafted from Sturdy Fossils. Upon hitting an enemy, it will stick to the enemy and inflict the Penetrateddebuff, dealing 3 damage per second. Up to six Bone Javelins can be pierced onto an enemy, dealing a total of 18 damage a second. Bone Javelins stuck in an enemy will dissipate after 15 seconds. Bone Javelins have no chance of dropping themselves after impacting blocks or hitting enemies.
Bone Javelins appear to have a strange effect on Granite Golems. When the Granite Golem turns invincible by crossing its arms, Bone Javelins will not do damage until the invincibility wears off, doing the damage via many 1s. It appears that the damage stacks over time, even while it is invincible.
The Bone Javelin is a powerful pre-Hardmode weapon with its high base damage of 20 and long sticking effect. Combined with Fossil armor, this weapon could easily two-shot most pre-Hardmode enemies and is still viable in early Hardmode. However, it lacks the piercing ability of the Bone Throwing Knife, making it most effective against single enemies.
The Penetrated debuff can never be applied to players, so it lacks a correct debuff icon. It instead uses a duplicate of the Distorted debuff's icon.
Bone Javelins act similar to a Daybreak which both stick to an enemy and inflict a stacking damage debuff.