Echo Echo is a playable alien.
Echo Echo can scream at ultrasonic frequencies capable of overloading machinery and stopping projectiles in mid-flight. He also has the ability to duplicate himself, not unlike Ditto, but different in that the clones aren't linked in any way, allowing entire groups to be knocked out without hampering the rest, and he can clone himself much faster than Ditto. His cloning capabilities seems limitless. By combining these two aspects, Echo Echo can create a "Wall of Sound", where he and his clones can redirect projectiles back to their source by bouncing them off of strategically placed clones, and "Echo Chamber," where he and his clones attack from all directions, and keep sending out sonic screams until the victim is knocked out or defeated (in a circle, as seen in Above and Beyond).