Some caterpillars defend themselves from predators using toxic chemicals, repugnant smells, or stinging hairs. Some camouflage themselves. Some mimic snakes. Some recruit ant bodyguards. Some create protective fortresses, or make warning clicks, or vomit up their guts.

And then there’s Uraba lugens, an Australian moth colloquially known as the gum-leaf skeletoniser, and even more colloquially known as the Mad Hatterpillar. Like all caterpillars, it grows by shedding its hard outer shell before expanding the soft body beneath. But every time it does, it keeps the part of the shell that once enclosed its head. With every moult, the stack of head capsules grows, eventually becoming a tall, tapering tower.

Yes, this caterpillar wears a hat built from its old heads.

A hat.