Bat Brain is a bat-based badnik created by Dr. Ivo Robotnik and later by Dr. Eggman during the reset world created by the Genesis Wave. It appears to function as a spy. Sometimes, it appears to have a Transylvanian accent.
Bat Brains were first seen in vast numbers along with a swarm of Buzzbombers. Sonic the Hedgehog saw them guarding one of Robotnik's airships. Accompanied by Antoine D'Coolette, Sonic was able to destroy the Bat Brains, Buzzbombers, and the airship. (OSM: #2)
Bat Brain was sometimes seen as more reliable than most badniks. For a time, he had the record for lasting the longest against Sonic. His best time of 37 seconds beat out Grounder by 20 seconds, though Coconuts found a way to cave in that record. He also managed to validate Moto Bug's report of a wedding between Sonic and Princess Sally, though nobody realized that it was a play. Bat Brain was badly beaten in this ill-conceived battle. (StH: #11, #18)
An upgraded version of Bat Brain was seen doing some reconnaissance, remote operated by Dr. Eggman. Through Bat Brain's optics, Eggman saw Bunnie Rabbot enter a large hole in the ground where a large explosion had happened recently. deciding that Bat Brain was not combat ready, Eggman sent Metal Sonic to investigate. (StH: #146)
Misfit Badnik Island
Bat Brain (the first model) was one of many badniks to appear on the Island of Misfit Badniks. Sonic smashed them up until Pseudo Sonic showed up to actually fight Sonic. Bat Brain was the genius behind the "Bighorn Challenge," which sank the island. When the badniks planned their revenge scheme by enlarging Pseudo Sonic, and the Forty Fathom Freedom Fighters intervened, Bat Brain was among the last badniks to fight, serving under Caterkiller's command. He suffered a hit from Bottlenose, a bigger hit from Pseudo Sonic, and the biggest hit when Big Fluke smashed the badniks and the island. (StH: #170, #185)
Appearing During Genesis
Multiple Bat Brains later appeared in Marble Zone during the events of Genesis, but this time they were created by Dr. Eggman. They appeared inside a ruin where Antoine decided to hide. They began to attack, but Sonic heard Antoine's pleads for help and destroyed every one of them. (StH: #226)
Bat Brain is capable of flight, and can boost his speed with his rocket booster. He has two skills, dive-bombing foes, and spy work.
- Bat Brain is based on the bat-based badnik of the same name (known as Basaran in Japan) from the Genesis Game Sonic the Hedgehog. The only design difference is the color (all purple, instead of blue with grey wings). The only place to find him is in the Marble Zone, making him one of two badniks, (the other being Roller) who appeared in the genesis version, but not the Game Gear version.
- The upgraded model is all silver, and resembles a roboticized non-anthromorphic bat.