Dubior

Dubior is a mid-boss appearing only in Kirby's Return to Dream Land. Oddly enough, it gives the Spark ability when inhaled, likely because the UFO ability isn't in the game. It is first found in Stage 5 of Nutty Noon.

Physical Appearance
It is a UFO-like robot that has two yellow eyes and an antenna that has three strips of metal that change from yellow to red. Its head is colored in a shade of metallic yellow and the underside of it is a coppery orange. Surrounding Dubior are 5 stubs of floating metal that are detached from it. The tips are orange and the tops near its head are yellow.

The EX counterpart is pink in color and has only one eye. The underside of its head is now dark blue and the tips of the revolving metal around it are pink as well. Dubior EX has more health and its attacks deal more damage than the original's.

Attacks
Dubior's attacks include a charged ram that deals lots of damage, a lightning-bolt attack from above that strikes repeatedly, and the ability to spawn Dubior Juniors - miniature missile-shaped versions of itself (2 in the main game and 4 in extra mode) which will zigzag around and may be inhaled to obtain Spark. A great opportunity to strike is right after the charged ram, due to the fact that it will sit there stunned for several moments. When weakened, it will shoot several orbs of electricity from its bottom at wherever Kirby is. Even just moving around is a form of attack for Dubior, as it will zip about at random locations above Kirby's head. Dubior is usually fought before a puzzle that requires the Spark ability to complete it. Many of Dubior's attacks resemble Kracko and Kracko Jr.

Dubior EX is a lot more unpredictable in battle. It darts around in the air much faster and charges more quickly. The charging attack is altered; instead of just charging ahead in a straight path, Dubior EX will loop in the middle of its ram to attack the player character if they try to jump. The Dubior Juniors it spawns are more numerous than before and make it harder for Kirby and his friends to avoid their flight patterns. Dubior EX can now use an altered version of its lightning-bolt attack. Instead of striking repeatedly, it sometimes fires along the ground and moves toward the player, much like Kracko's signature attack.

Trivia

 * Dubior's coloration in normal mode may be a homage to R.O.B..
 * Dubior bears a bit of a resemblance to a mechanical version of the mid-boss from Kirby's Dream Land 2 named Master Green. Both are a shade of yellow (Master Green in his artwork) and give the same ability (Spark). The detached parts of metal that encircle Dubior's body somewhat look like short tentacles, further adding onto its appearance of a robotic jellyfish.