Migos' most famous line just got the bling treatment.

Offset just dropped $100k on a ridiculously iced out chain in the shape of a raindrop. It's obviously inspired by their hit, "Bad & Boujee" ... which, for anyone sleeping out there, starts "raindrop, drop top."

Elliot Avianne of Avianne & Co Jewelers tells us the raindrop pendant is 32 karats which makes for a total of 65 karats when you add in the chain. Offset came up with the idea and wanted it ready in time for Quavo's bday this week -- he turned 26 on April 2.

The crazy part ... Elliot got the piece done in 48 hours, so ...

Yeah, Offset's diamonds a choker (glah) / Holdin' fire with no holster (bloaw).