|Series||Fully Cowled Mini 4WD|
|Release Date||March 14, 2020|
|In fictional media|
|First Appearance||Bakusou Kyoudai Let's & Go! Return Racers!|
|Owner|| Retsu Seiba (Return Racers!)|
Shun Daichi (Let's & Go! Tsubasa)
It was featured in the manga Bakusou Kyoudai Let's & Go! Return Racers! as the teenage Retsu Seiba's machine. It was also featured in Let's & Go! Tsubasa: The Next Racers where the older Retsu gave it to Shun Daichi.
The Cosmosonic has the fully cowled body design that is similar to the Great Magnum R, but sharper. It retain the rear spoiler from the Great BlastSonic. As with the rest of Retsu's Sonic machines, it has white bodyshell, with red and green stripes mixes onto it. it has white bodyshell, with red and green stripes mixes onto it.
It was equipped with the yellow, small diameter 5-spoke A-spoke wheels paired with the black low-profile tires. Both the chassis frame and A parts were molded in black.
|Fully Cowled Mini 4WD series|
|Super-1||Magnum Saber* · Sonic Saber* · Tridagger X* · Black Saber · Spin-Axe · Proto-Saber JB · Victory Magnum* · Vanguard Sonic* · Beak Spider* · Neo-Tridagger ZMC · Fighter Magnum VFX* · Ray Stinger* · Shining Scorpion* · Bergkaiser*|
|Super-FM||Brocken Gigant · Gun Bluster XTO*|
|Super TZ||Cyclone Magnum* · Hurricane Sonic* · Cyclone Magnum TRF · Diospada* · Beat-Magnum* · Buster-Sonic* · Beat-Magnum TRF · Fire Stinger|
|VS||Spin-Viper† · Diomars-Nero†|
|AR||Z Wing Magnum · Great BlastSonic · Beak Stinger G · Proto-Saber Evolution† · Tridagger WX|
|FM-A||Great Magnum R · Cosmosonic|
|* denotes Premium version available; † denotes racing chassis re-release of a Mechanical Mini 4WD car|