The fully grown form of the Vampire Plant, Tigris Flower, and the first monster Ultraman Taro fights after coming to Earth. Astromons attacks with a whip for a right hand and sickle for a left hand, as well as the dissolving liquid spewed from the center of Astromon’s chest flower.

Astromons appeared from underground at an oil refinery under attack by the Oil Terrible-Monster Oil Drinker. Astromons attacked the Terrible-Monster and then consumed Oil Drinker whole through the mouth of his flower. However, the members of ZAT also at the same refinery attacked Astromons, making him fly away.

Astromons reappeared in central Tokyo and attacked the city. Astromons closed in on the ZAT base and its members once again went up against the space monster. They confused Astromons with electrical weapons, but Kotaro Higashi’s Super Swallow was shot down. At that moment Ultraman Taro appeared. Taro was damaged by Astromons dissolving liquid, but Taro defeated the monster with his Strium Beam.