Explanation 1. A strange bone inside a hollow part inside the pelvis of the Jakelocaltrus' stomach, connected by flexible muscles and tendons which can snap forward, making vibrations through its body 2. The horn of a Xarryganitus never stops growing, so it needs to carve its horn on hard materials, sometimes even breaking their horn, allowing them to not carve their own horns.

This feels cursed just seeing the weird formations of the bones and the anomaly in Jakelotracus' stomach