Cicada shell

A Cicada Shell is a bug that can be caught in and. Technically, it is just the exoskeleton left behind by a cicada nymph, making it the only bug in the game that is not living. Cicada Shells can be found on trees; the player can run or walk past the trees without scaring the bug away. The only way to make the Cicada Shell disappear is to shake the tree or hit the tree with an axe, causing it to drop to the ground and disappear.

Donating to the museum
As with all insects in the Animal Crossing series, Cicada Shells can be donated to the museum followed by a small talk by Blathers, the curator.

In
It can be found in the top section of the upper right room in the bug habitat of the museum, with the other cicadas.

In
Once donated, the cicada shell can be found on the trees right in front of the entrance to the bug exhibit. They are also found in the second room nearby where ants are located, this may be referencing the 17-Year Periodical cicadas.