These monsters are animated statues which resemble Chess Knights with Unicorn horns. They have appeared as enemies in all of the Seiken Densetsu games following FFA and in FFA they can be found in the sprite data of the game as what would appear to be a boss judging by their size.
Unused Sprite
A Chess Knight enemy did not actually appear in FFA. This sprite of one, however, exists in the game’s data, so it must have been planned as an enemy for the game at one time.
In SoM Chess Knights are classified as Insects.
Chess Knight / Unicorn Head (J)
Chess Knights can be found in the Fire Palace as well as in Pandora’s Ruins. They usually cast Speed Up on themselves before they start to fight. They attack by hopping at you as well as trying to hit you with their horn. On Gold Isle you can buy a helmet bearing their likeness.
In SD3 Unicorn Heads are classified as a Insects.
Unicorn Head
Unicorn Heads are controlled by the Altena Magicians and are so found in their castle. They are found in Forcena Castle when Altena attacks. They will sit still as a statue until you get too close to them. While they are sitting still they can be hit by fullscreen techniques or spells, but they will take no damage until activated. They stab with their horn and also use a Rush attack.
Gold Unicorn
These Gold Unicorn Heads live in the Dark Castle. They have a Double Critical attack that does not deal damage, but rather puts your characters to sleep if it hits them.
In LoM Chess Knights are classified as Poltergiests.
Chess Knight / Unicorn Head (J)
An overwhelming wish to fight brought this Chess piece to life. They are found scattered through out the world and at high levels will drop the very rare Adamantite metal. They attack with hops, stabs and beams and will occasionally turn into a Queen or King piece as a taunt. As a pet they raise your defense.