Sonorosian

Sonorosians are seemingly humanoid creatures made of sound from the planet Sonorosia.

Appearance
According to Derrick J. Wyatt, Sonorosians are made of living sound waves, so they wear white containment suits made of silicon.

Sonorosians have robot and synthesizer-like voices.

Powers and Abilities
Sonorosians can scream at audible to 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 aren't linked in any way, allowing entire groups to be knocked out without harming the rest.

Sonorosians can detect vibrations in the ground. Using their sonic screams, Sonorosians can use echolocation. Sonorosians can channel vibrations to enhance their screams.

Sonorosians can transmit sound waves through speakers, such as phones. Sonorosians can use their sonic screams to create a forcefield.

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.

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