An icon used by drug smugglers in the southwestern united states. It was originally a symbol used to identify those who were muling drugs across the united states border, but has sense evolved to be a symbol for smuggled drugs on the whole.

The term has gained notoriety outside the underground from a September 23rd 2006 story broken on abc's news program 20/20.
Seeing a blue balloon on a car window you know they traffic drugs.
by Joseph Timberland October 26, 2007
Get the blue balloon mug.