Sandy

Sandy is a Coral Shiver nurse shark, Third in the Line and adoption mother of Gray the megaladon, after finding him by the reef after an underwater explosion. Thinking he was a reef shark, she took him in. Her two other children besides Gray are Riprap and Ebbie. She can get angry at times with Gray, but is usually bright and happy.

Before Shark Wars
Sandy, a rogue, was swimming in the Carribi Sea and encountered a great underwater volcanic eruption. After it ceased, the water smelled of sulfur and everyone became dark and gloomy. At that moment she discovered a shark floating in the water. She waited for a while to see if its parents would come, but then, after they didn't, believing he was a reef shark, took him in and named him Gray, after the dark and gloomy Carribi on the day she found him. As her adopted son Gray grew up, she began to have her doubts about whether he was truly a reef shark.

Shark Wars
Sandy punishes her son Gray for swimming away from the reef by making him unable to swim away from it for a week. She also tells him that this year he cannot go to the Tuna Run, an event where a siege(a million fish) of fish or even more swim and a feeding frenzy occurs because it is just too dangerous. Later on, when Coral Shiver discovers that Gray and his best friend Barkley have alerted Goblin Shiver about their homewaters, she begins to cry and tells Gray that he will have a little brother and sister and to meet her at the Tuna Run before Gray is banished from Coral Shiver. She, along with the rest of Coral Shiver, excluding Atlas and Overbiter due to their deaths, are evacuated when Razor Shiver bulls attack their camp, and they move a more hidden reef in Razor Shiver's territory. At the end of the story, Gray sees her at the Tuna Run, but cannot communicate with her or find her after that.

The Battle of Riptide
Gray and Barkley find her and the rest of Coral Shiver living in a hidden reef in Razor Shiver's homewaters. She shows Gray her new children, Riprap and Ebbie. Later on, after Gray and Barkley take the rest of Rogue Shiver to Coral Shiver, she tells Gray that she is not his mother, and that one day, she found him floating in the Carribi Sea and named him after the dark and gloomy ocean that day. When Gray asks if he can still call her mom, Sandy responds with a yes.