Cuco

Cuco is a hippocampus who appears in the Elena of Avalor special, "Song of the Sirenas".

Elena of Avalor
Cuco makes his debut in "Song of the Sirenas"

He appears with Princess Marisa and Prince Marzel when they first see Princess Elena on Scarlett Turner's ship. They get attacked, but Elena saves them. They retreat, but Marisa suggest they talk to the princess so she can tell the humans they're friendly. Princess Marisa talks to her parents, but her father refuses to talk to the princess. Marisa goes to talk to Elena anyway, Cuco suggest to Marzel that they follow and make her she doesn't get hurt.

The Secret Life of Sirenas
Cuco's only appearance in the The Secret Life of Sirenas shorts is in the short "Off to the Races".