The Little Sea Monster - Horrific Fairy Tales, #3

The Little Mermaid meets Creature from the Black Lagoon in the third book of the Horrific Fairy Tales Series, when a sleepy seaside town is stalked by vicious monsters from the watery depths.A little mermaid with a big appetite... Perpetua is a naiad, a beautiful sea creature. Beautiful-and deadly. Like all her kind, Perpetua must hunt and eat humans to survive. When a hunt goes wrong, Perpetua saves the life of a human.
But when her good deed is discovered, Perpetua's fellow naiads cast her out. Cursed by the sea witch, Perpetua is transformed into a human. Now Perpetua must navigate an unfamiliar world. Luckily, she has one friend: Demetri, the boy she saved. Unluckily, Demetri is a naiad hunter. Perpetua knows he can never find out what she was, or how many countless humans she's killed. Keeping this secret becomes more difficult once Perpetua makes a terrible discovery: she still hungers for humans and will not survive without feeding on them.
Worse yet, Perpetua has developed feelings. Feelings for Demetri. Feelings that make her dread taking another life. With only weeks until her human body gives out, Perpetua must decide if she will live as a killer. or die for the humans she has come to love. The Little Sea Monster combines carnivorous mermaids, forbidden love, and shocking betrayals in this reimagined tale, where everyone is hiding what they are-even from themselves.