Agro is the player's equine companion in the game Shadow of the Colossus.
Agro has a black/grey coat, with a white marking on her forehead. If a save file from Ico is on the memory card this marking takes on the appearance of the 'I' from the game's logo.
In-game Agro is referred to as a male (in English, at least), though Fumito Ueda considers her female.