Spectator is a beholder that appears in Baldur's Gate II: Shadows of Amn, Baldur's Gate II: Throne of Bhaal and Baldur's Gate II: Enhanced Edition.
Spectator is first met in City of Caverns, where he's guarding a chest containing Sekolah's Tooth. He is bored of his assignment so it is possibile to take the treasure without battling him.
He is met again later in Sendai's Enclave. He will suggest that Captain Egeissag challenge the protagonist to a one-on-one fight.