The Hardshell Crackerworm (Sireniovermiops echinophagus) is a durophagous species that has been living in Atlantic seagrass meadows for 15 million years. Descended from Bridge Worms, it evolved for shallow waters and possesses specialized teeth for voraciously devouring shellfish. However, during breeding and mating seasons, the males emerge from the sea, where they are forced to fight or eat each other according to the female's wishes, leading to gruesome consequences and exhibiting somewhat cannibalistic behavior. The male chosen by the female must also fulfill another request: to have sex with each other.
When a female is pregnant, she can give birth to a maximum of two offspring, due to the narrow structure of her reproductive organs. Newborn Crackerworms emerge from the mother's reproductive organs for the first time as blood flows into the sea, just like in an ichthyosaur, cetacean, or hippopotamus, but they must separate at least six months later and embark on a harsh journey out into the world. Finally, because Crown-of-Thorns were not successfully eradicated in the Atlantic, their descendants are just as greedy as their ancestors, but Crackerworms counteract this by spitting viral saliva (this saliva contains a pathogen descended from SSWD) from their mouths to prevent them from walking, a death trap for the starfish. However, nature doesn't always act according to human expectations.