Beneath the warty skin are 12-14 stout grooved spines, each with a large venom sack at its base.
Punctures are extremely painful and can result in loss of limb or death.
To add insult to injury, these fish are masters of disguise and hard to find amongst the coral rubble. Luckily for people, stonefish usually rest under or against rocks, limiting chance encounters. Not so lucky for their prey. Sitting still as a, well, stone, these fish are sit and wait predators. When a small fish swims too near to the large mouth, a sudden gulp seals its fate.