The Iron Bulge is a device that has a 100% chance to attract Laxus's lightning. Laxus then appears in a chippendale outfit, complete with bowtie and nothing else. The iron bulge was designed by Amberleh because it was forged in the fires of Amber's extreme jealousy for Mirajane stealing her true love away from her.
The Iron Bulge can absorb an infinite amount of lightning. When it absorbs enough, it transforms into Steel Bulge, giving the user temporary invulnerability. When its electric storage is spent, it reverts back to a Rusty Bulge.
Impenetrable defense as Steel Bulge
Selectively penetrable defense (based off of the user's current INT)