The Neogolem is a hybrid weapon created by the San Fransisco branch of the Society.
During the flashback that details Bianca's introduction to Reiichiro Kirasagi, a Neogolem went on a rampage inside of a Society facility. Bianca was trapped in a room with the device and faced impending doom, but Reiichiro was able to intercede and protect her from the weapon.
In episode six, which takes place years after Bianca's flashback, Bianca is testing the combat abilities of Ryuji Kisaragi, the son of Reiichiro. The test is conducted using a Neogolem and once again the weapon goes berserk, although foul play may have been involved this time. Bianca is unable to defeat it but luckily Ryuji and Rose are able to take it down before anyone is harmed.