Cetus

Cetus is a sea monster and character in the Endless Summer series. It first appears 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
It immediately has a hostile encounter with Jake, Sean, and possibly your character if he/she joins them on the speedboat. A premium option (if you choose to join Jake and Sean in the first place) gives you the opportunity to fight it with a Semtex found in the speedboat and a flare gun found in the marina (provided the latter isn't used before).

Trivia

 * Michelle's Catalyst Idol shows her getting killed by the Sea Monster.
 * Jake's nickname for Cetus is Freakachu, a reference to the Pokémon character Pikachu, because of its electric attacks.