9 Volt: Brown Nugget starts at half charge after use.
Car Battery: Two flies will be spawned instead of one.
Sacrificial Altar: Spawned fly turrets count as familiars for sacrificing, although dropping the Brown Nugget will despawn the last fly turret, older ones will remain and can be sacrificed.
Brown Nugget was originally an unofficial item which was supposed to showcase the modding capabilities of Afterbirth+ in the PAX 2016 livestream. However, all items included in the demo were later added to the final game.