Toxikarp

The Toxikarp is a Hardmode ranged weapon obtained from fishing in The Corruption at any depth. It emits greenish bubbles that travel in the direction aimed for a short distance before ascending rapidly, and can cause the Poisoned debuff. If the bubbles do not strike a creature or a block, they will eventually ascend into space. The bubbles can pass through platforms without breaking. If the bubbles come into contact with water, they will instantly start to ascend. The Toxikarp does not require any ammunition.

Its best Modifier is Unreal.

Tips

 * As it doesn't require ammunition, has decent damage output, and can be obtained as soon as you beat Wall of Flesh, the Toxikarp can be a great sidearm well into Hardmode.
 * the spelling may be a reference to the Pokèmon Magikarp

History
Carpe Toxique

Trivia

 * Toxikarp is a reference to Magikarp which is from a popular RPG game called Pokemon