Charonia

The shell of the giant triton Charonia tritonis (Linnaeus, 1758), which lives in the Indo-Pacific, can grow to over half a metre (20 inches) in length.

One slightly smaller (shell size 100–385 millimetres (3.9–15.2 in) but still very large species, Charonia variegata (Lamarck, 1816), lives in the western Atlantic, from North Carolina to Brazil.

[5] The giant triton has gained fame for its ability to capture and eat crown-of-thorns starfish, a large species (up to 1 m in diameter) covered in venomous spikes an inch long.

The triton grips its prey with its muscular foot and uses its toothy radula (a serrated, scraping organ found in gastropods) to saw through the starfish's armoured skin.

Tritons ingest smaller prey animals whole without troubling to paralyse them, and will spit out any poisonous spines, shells, or other unwanted parts later.

X-ray image of the shell of Charonia lampas
The struggle between a starfish and an Atlantic triton can last up to an hour before the seastar is subdued by the snail's paralyzing saliva.
Fossil shell of Charonia appenninica from Pliocene of Italy