Also known as the "Artillery of the Underworld," the Eyeball-Ones use their antennae to gather ethereal energy drifting in the air and concentrate it into a deadly beam shot directly from their specially evolved giant yellow eyes. If Sonic manages to avoid the energy beam, he can exploit the Eyeball-Ones great weakness - they can't move much, and are vulnerable to some high-speed slashing. Ones with pink eyes are immature and cannot throw off the energy wave. — Description, Sonic and the Black Knight US website
According to developers notes, the Eyeball-Ones were designed to look like sea creatures.
The Eyeball-Ones resemble tall slugs made of slime. The bottom of their body resemble a spread-out pool while their upper body is a bend-over lump resembling a slumping humanoid body. On their back they have four antennas and where heads supposedly are they have a single, specially evolved eye dripping with purple slime which is surrounded by sharp teeth. Their skin is dark blue with glowing red medieval markings on the rim of their bottom, waist, back and antennas. They also wear metal plates on the front that resembles a helmet.
The Eyeball-Ones do not come in as many numbers at the members of the Soldier-One variant of enemies. They are first encountered in Knight's Passage and can after that be found in several other areas. When they shoot their energy beams at the playable character, the player can effectively block them with Guard. Like most other Knights of the Underworld, the Eyeball-Ones can be defeated with a single, well-aimed sword slash.
The Eyeball-Ones attack primary with their energy beams. When doing so, they shoot two beams in succession. After that, they have to recharge for a couple of seconds before they can fire again. They can also attack by simply moving into the playable character, causing damage. When too far away from the playable character, the Eyeball-Ones can teleport closer to them.
Noticeably, the Eyeball-Ones with pink eyes are immature and cannot throw off energy waves.
Powers and abilities
The Eyeball-Ones are able to teleport to different locations by emerging from black voids. As their special trait, they can use their antennas to gather the ethereal energy drifting in the air and then concentrate it into a deadly energy beam which they can shoot directly from their eye. The Eyeball-Ones' bodies are also elastic as they can be bend pretty out of shape when hit with a kick from Soul Surge.
The Eyeball-Ones weakness is that they are slow and cannot move very much, making them vulnerable to high-speed swordplay.