Sonorosian

Sonorosians are creatures made of living sound waves encased in containment suits from the planet Sonorosia.

Physiology
Sonorosians are made of living sound waves, but wear small, white and green containment suits made of silicon. The green circle-shaped indents on the back of a Sonorosian's hands are sound holes that help them resonate. They wear headphones so they cannot be hurt by their own sonic screams.

Powers/Abilities
Sonorosians can scream at ultrasonic frequencies, capable of overloading machinery and stopping projectiles in mid-flight.

Sonorosians can duplicate themselves, similar to Splixsons, but different in that the clones are not linked with each other in any way, allowing entire groups to be knocked out without harming the rest.

Using this sonic screams, Sonorosians can detect vibrations in the ground, use echolocation, and create forcefields.

Sonorosians can channel vibrations to enhance their screams. They can also can transmit their sound waves through speakers, such as phones.

Sonorosians are quite strong and agile for their size.

Weaknesses
Because their appearance is a containment suit, a Sonorison's body is rather fragile. That means they can easily be destroyed in battle, such as by an Aerophibian's neuroshock blasts, the fire attacks of either a Methanosian or a Pyronite, and a Cerebrocrustacean's electric beams.

Sonorosians can be immobilized in ice, such as a Necrofriggian's ice breath.

There is a limit to the number of duplicates a Sonorosian can make, which depends on the amount of energy they have access to.

Behavior
Sonorosians speak using voices that sound robotic, almost like a voice synthesizer.

Omnitrix Transformation
The Omnitrix's Sonorosian representative is named Echo Echo, who first appeared in the Alien Force episode "Ben 10 Returns: Part 2". Echo Echo has appeared in almost every subsequent series except the reboot.

The Ben Tennyson of Dimension 23 has an equivalent of Echo Echo named Copy Copy, who was confirmed to exist in the Omniverse episode "And Then There Was Ben".

Echo Echo has also been used by Albedo. Despite not appearing on-screen, it is confirmed that Echo Echo is available in Mad Ben's Omnitrix.

Etymology
"Sonorosian" is a play on sonic and sonar.