There is a tale of a witch and her son. Married in satanic tradition, the husband died in obscure circumstances shortly after impregnating his beloved. She bore the child and raised him as a warlock. He was all that reminded her of her late betrothed and could not live without the boy. They lived happy for some years until something changed. The son developed a dark obsession with the sea. He would spend days and days at large on a boat fit only for himself, practicing spells and rituals kept tightly secret. One day, he simply did not come home. The witch became sad for she knew, being his mother or not, she had lost her place in his heart. Walking along the beach one day she heard a call, that of a mermaid. She ran into the ocean until knee-deep and spoke with the creature. "The man you seek to reclaim we seek to discard. This offspring of yours has been tainting our home waters with his Dark Arts and the flora and fauna have began to die." said the mermaid. "This interests me little", answered the witch. "Oh, but there are ways to stop this madness of his... you need to contact the Sea Demon, using these." The mermaid handed the unholy matron two vials: one of black water, the other of iridescent sea salts, and then swam away.
The witch raced back to her cottage, her heart swelling. She prepared a ritual and mixed the vials' contents. Through the pentacle drawn on her floor rose the most nauseating, foul-smelling mass resembling a humanoid skeleton covered in rotting fish carcasses and with the head of a shark. "What dare you ask of me, witch!? Oh! Oh... Say nothing, I understand just by reading your heart. I am the demon your young son has been gathering offerings for in exchange for special powers. I have bound him to me, forget about him!" "I can't!", replied the witch, "he is my world... I need him free of your hold." The demon was obviously angry, and more powerful than any she had seen before, not very far in rank from Satan himself! "I will make you a deal. Give me your life and I will let go of your son's. It is only fair, no? One for one..." The witch fell to her knees and cried. Either way she would lose him, but at least in one he would be free. She quelled her sobbing. "I accept..." After she spoke the words she fell to her knees, a milky white wisp emerging from her mouth and gathering in the demon's hand.
With a snap of his fingers, the Sea Demon made the boy appear, falling to the ground on top of his mother's body. He was no more than 9. "Your mother made a deal with me, boy! Her life for yours. A pity really, you showed promise. I guess I do have a soft spot still for my worldly pleasures." The child raised his head a bit, puzzled. "In any case, you are free! GO, before I change my mind and draw you back in." As the boy scampered to leave the hut, the demon laughed maniacally, itching him to look back. "Here is a present, from father to son." A jolt of violet light shot from the demon, who disappeared, straight into the lad's back. Screaming, he fell to his knees and then on his back, convulsing in pain as his body twisted and deformed, leaving his skin purplish blue, fingers clawed, form slender and his head... oh his head... It was as if a four-tentacled octopus had perched on his neck. When he could stand he dashed off into the woods, never to be heard of again.