Eyeball monsters

Eyeballs of many varieties have been found in Castlevania games.

Big Eyes
The Big Eye is a signature enemy for the first two Game Boy Castlevania games (Castlevania: The Adventure and Castlevania II: Belmont's Revenge and has a major role in Castlevania: The Adventure ReBirth. It rolls across the screen in one direction, and often times there are an endless stream of them, initially falling down from a high place.  When they are struck, they often explode, which can destroy some platforms that they are rolling on.  A giant form of the Big Eye appears as the end boss of the first stage of Castlevania: The Adventure ReBirth.  It bounces and rolls around and ejects smaller Big Eyes from its pupil.  It can also turn around and fire a large beam.  Dracula's final form in the game also summons Big Eyes out of mystical symbols.