Powelliphanta is New Zealand's giant carnivorous snail – a national treasure, a conservation icon, a creature that eats other snails and grows a shell like stained glass. It is protected, threatened, carefully managed. You can see one in a predator-free sanctuary if you are lucky: a black, glistening body, a shell striped in amber and mahogany, moving slowly across a bed of moss. It is magnificent. It is also a shadow. Because there used to be a giant – a Powelliphanta the size of your fist – and it is gone. A living Powelliphanta is already impressive – a shell the size of a plum, a body that stretches to the length of your thumb. It is a predator. It hunts other snails, following their slime trails, tracking them through the leaf litter. When it catches one, it wraps its body around the victim, pins it down, and rasps a hole through the shell with its radula – a toothy, tongue-like organ. Then it eats the occupant alive. Slowly. Now imagine that snail bigger. A shell the size of a tennis ball. A body that stretches to the length of a banana. A predator that could take on larger prey – giant earthworms, large slugs, even small wētā. That was the giant Powelliphanta, and it was the tiger of the leaf litter. It crawled. Slowly. Relentlessly. A snail's life is measured in centimetres per minute, but it gets where it needs to go eventually. It laid eggs – small, leathery, pearl-like capsules – in the damp soil under rotting logs. It lived for years, perhaps a decade or more, growing slowly, adding whorl after whorl to its shell. It was a creature of patience and appetite, and for millions of years, that was enough. Possums, rats, pigs, and habitat destruction destroyed it. When Europeans arrived, they brought the common brushtail possum from Australia. Possums love snails. A Powelliphanta is a protein packet wrapped in a calcium shell – easy to find, easy to crack, easy to eat. Possums wiped out entire populations in a single season. Rats – ship rats, kiore – also eat snails. They crack the shells, slurp the meat, leave the fragments on the forest floor. Pigs root through the leaf litter, crushing everything in their path, eating snails by the dozen. At the same time, the lowland forests of the South Island's western slopes were cleared for pasture and pine plantations. The giant snail needed deep, damp, undisturbed forest with thick leaf litter and abundant prey. Take away the forest, take away the snail. The smaller Powelliphanta survived. They retreated into the remaining fragments of forest, grew smaller, grew shyer, grew less visible. Some are still threatened, still teetering on the edge. But the giant form is extinct. A few shells in a cave, a few fragments in a museum drawer, and the memory of a predator that used to glide through the dark. We introduced the possum. We cleared the forest. We crushed the snail. Then we wondered why the titan disappeared.