This Boomer resembles a large spider-like creature and is designed for extreme combat situations. It walks on four clawed legs and is capable of leaping significant distances and can climb walls. It has a single arm on its right side that ends in three razor-sharp talons that can impale targets or crush them. It is also armed with a gatling gun and a laser cannon on its back. Its initial combat demonstration revealed that its artificial intelligence was flawed; its IFF subroutine failed to recognise Dr. Yuri and the attending military inspectors as non-combatants and the robot attacked them. Yuri narrowly managed to shut it down before it broke into the control booth and skewer one of the inspectors.
When Dr. Yuri was ordered by Largo to re-capture the sentient Boomer ADAMA, he deployed the EM-302 and sent it into Geo City to attack Priss Asagiri. Priss was saved by her fellow Knight Sabers and equipped her Hard Suit to battle the deadly Boomer. Using additional armaments, Priss managed to destroy the EM-302 after impaling its head with an energy sword and sending it falling from a skyscraper.