Celis, Siren of the Seas is a secondary antagonist in the 1992 Commodore Amiga action platformer game "Kid Gloves II: The Journey Back" by developer Digital Magic Software. She is the boss of the second area, Water Island.
From the game's instruction manual: Because his goldfish were to placid and his piranhas too small, Wievallard employed a terrifying mermaid to guard his coral reefs. Going by the name of Celia she has dazzled men with her beauty, only to dash their hopes and dreams by removing their heads. She'll prove to be a handful!