"For example humanity, they are more of insects from our perspective."
- ―Alien Cool's point of view towards humanity.
Alien Cool (クール星人 Kūru Seijin) was the first alien that appeared in the series, Ultraseven. Also known as Alien Kuuru, his home world is Planet Cool. Alien Cool collects human specimens using a vaporizing and teleportation ray from his invisible flying saucer. He commenced attacks on an industrial area; all a part of an attempt to cause the TDF (Terrestrial Defense Forces) to submit into unconditional surrender.
Subtitle: Space Hunter (宇宙ハンター Uchū Hantā)
For the past few weeks, reports of people mysteriously disappearing became a major concern. The Self Defense Force had the Ultra Guard on the job, a special agency designed to stop alien attacks. While two members were sent to investigate if something would happen in a nearby forest, a drifter by the name of Dan Moroboshi made himself known and proved to be a bit of a nuisance. Dan warned the Ultra Guard that they were in danger, but no one believed him until a police car that was driving ahead of them disappeared. After being shot at and returning to their base, the Ultra Guard concluded it was the work of an invisible alien. Alien Cool hijacked the televisions and made the Ultra Guard watch as his invisible ship destroyed an entire oil refinery district and would soon attack Tokyo. Dan came up with the idea for a special spray paint and it worked once the Ultra Guard took flight. Cool flew his ship to a nearby canyon after it was hit. After he was forced to land, he summoned five miniature saucers which flew out to menace Earth. Suddenly, Dan summoned a capsule monster by the name Windom. Windom destroyed two of them, but was quickly called back, with Dan Moroboshi then changing into Ultraseven. Ultraseven infiltrated Cool's saucer, used the Emerium Beam on the controls, sliced Cool in half with the Eye Slugger, and freed the missing people he was holding for experimentation. Once Ultraseven took the saucer to space and destroyed it with the Emerium Ray, Dan became the latest member of the Ultra Garrison.
- Voice actor: Koji Yada
- It is stated that Planet Cool has very poor resources forcing its natives to plunder from other worlds in order to advance in terms of technology. The planet is also said to be protected by the same cloaking technology used on their ships.
- An unused concept was for the Ultra Guard and Dan to visit Planet Cool in order the rescue captured citizens.
- In the Turner Network Television dubbed version, his name was Emperor of Zundar.
- Cutscenes of Alien Cool were used in the episode of 'Space Ghost: Coast to Coast' titled "Here's Johnny". The short episode featured an English-dubbed scene of Alien Cool playing the role of long-time TV talk show host Johnny Carson. Link to episode: 
- Height: 1.23 m
- Weight: 43 Kg
- Origin: Planet Cool
- Powers and Weapons
- Levitation: Alien Cool can levitate for an unlimited amount of time.
- Invisible Saucer: Alien Cool has a saucer capable of bending light, making it invisible. This saucer can also fire energy balls that can not only capture humans, but also range from destroying human sized rocks to entire buildings. The saucer can also take over communication devices like televisions.
- Miniature Saucers: From the main saucer, Alien Cool can release five smaller saucers, each with a laser ranging from capable of destroying human sized boulders to burning monsters like Windom.