MegaCorp Rivet Bots were large, black MegaCorp-manufactured robots that shot at enemies with rivets fired from two blasters upon sight.
They were originally designed as construction robots, but some of them were converted into police forces of Megapolis. They also engaged Ratchet, but it was unlikely that they malfunctioned like other robots in the city, and more sensible explanation was that they attacked him because he was wielding a gun. Contrary to this, the Monsterpedia describes that some also went rogue. There were two of them in the Boltaire museum.