Cetus

Cetus is a sea monster and character in the "Endless Summer" series. It gets its first appearance in Book 1, Chapter 11.

Appearance
Cetus is shown to be a gigantic, reptilian creature covered in scales. It has horns where its eyes should be.

Your Character
They immediately have a hostile encounter when he/she tries to save Jake and Sean.

Trivia
Michelle's Catalyst Idol shows her getting killed by the Sea Monster.