Cornulitida
This organism has been considered into different phyla, such as: coral, worm and mollusks. Survived from the Ordovician to the Devonian age, and often had a shell to protect itself from predation, this organism was a predator and could repair its shell due to failed predation. Later after the Ordovician period this organism adapted to the environment by forming thicker shells or a spine like cover as well.