Trilobite

The Trilobite is a stand-alone fossil that can be donated to the museum in all Animal Crossing games to date.

Donating Trilobite in Wild World
''Hoo my, simply marvelous! This fossil is an outstanding specimen. Trilobites existed long before the dinosaurs, I'll have you know. At the time, there were very few enemies, so they thrived, wot! For protection, much like a...blech...pill bug, they would roll up into a ball. Oh, forgive me babbling! The very thought of these beasts gets me atwitter!''