Gandarewa is an enemy in Final Fantasy X. It is encountered on the Mushroom Rock Road, and on the Moonflow. This enemy has high Evasion and Magic Defense, so Wakka's normal attack and Lulu's Water magic are good ways to take it down. It casts Thunder, so Lightning-resistant armor will help.
In Persian mythology, Gandarewa is an evil water demon. This is ironic, considering it is Lightning-elemental in the game.
The Japanese name for the enemy is Gandharva. Gandharva (Sanskrit: गन्धर्व) is one of the lowest-ranking devas in Hinduism and Buddhism. The Final Fantasy X BradyGames Official Strategy Guide incorrectly lists the enemy's name as "Gandarva".