Belemnite guard

A Belemnite guard is the fossilized internal shell of an extinct marine cephalopod related to modern squid and octopuses. It is a spike-shaped, dense structure that helped the creature control its buoyancy and movement in the water. When Belemnites died, these guards often settled on the ocean floor and became preserved as fossils. Today, they are valued by collectors and can provide clues about ancient marine environments and the Earth's geological history.