Baltan

The Baltans are microscopic creatures who escaped their world when it was destroyed while they were doing some nuclear testings. Roughly 60,600,000,000 microscopic Baltans came to the planet Earth, originally because of engine trouble with their spacecraft. After searching for sufficient technical components to repair their engines at a science facility, they later decided to claim Earth as their own. When they landed on Earth, the single Baltan alien appeared to Humans were either Human size or gigantic size; this is actually large group of the Baltan united.

The Science Patrol tried to negotiate with the Baltans, suggesting Mars as an alternative home for the Baltans, but the Baltans claimed Mars was less than optimal. Shin Hayata, Ultraman's host, suggested that the Baltans could live on Earth in peace if they obeyed Human laws but Baltans were not willing to make such a compromise (and that was before anybody learned of the Baltans' vast numbers).

Eventually the Baltans were going to wipe out life on Earth, but Ultraman destroyed a giant Baltan and the spaceship with the Specium Ray. It turned out that Baltan are very weak against Specium substance, which is also found on Mars and likely indicates their rejection of the red planet.

Despite this defeat at the hands of Ultraman, the threat of the Baltan does not end and Ultraman himself later encounters another Baltan (known as Baltan II). They attack Earth once again when the Science Patrol went into space to rescue the Ohtori spaceship.

Hayato's fellow Ultramen also fight these aliens.

Abilities
Baltan's claws are capable to release powerful energy missles or a paralysis ray. It can can take over a Human's mind and use one as translator. It also has flight ability and may project multiple illusions of itself to confuse the enemy. By disassembling and rearranging, it look as if a Baltan can teleport over short distances.

Baltan II shares the abilities of mind control, growth and teleportation with the first one encountered on Earth. Instead of a paralysis ray, it possesses a flash stun light that is emitted from claws in its stead. It can generate a gravity storm and increase or decrease gravity at will. To protect itself from Specium, it may open up its chest to reveal reflective mirrors that provide protection from energy attack. However, this does not work against Ultraman's Ultra Slash energy saw. Its other method of protection is an energy shield.