The Brain Golem is a recurring boss in the Gradius series. It first appeared as the very first boss of Salamander, later appearing in the boss rush sections of later games in the series.
As it's name implies, the Brain Golem is a giant floating brain, with a large eye on it's front which acts as it's weak spot, and sometimes various smaller eyes along it's body. It also has two tentacle arms, which acts as it's main form of offense. They always follow the player's movement, attempting to ram the player. It will also shoot from it's arms, depending on the difficult setting and/or current loop.