The Money Blimp was a giant airborne money-carrying blimp.
At some point prior to the mid-1970's, this gigantic blimp was launched by Scrooge McDuck and hidden among the clouds, concealing his fortune in an effort to put it out of the Beagle Boys' reach. The plan came literally crashing down when a drought caused unaware parties to shoot at the clouds in an effort to cause rain, causing the balloon to puncture and all the money to come raining down instead.
Behind the scenes
The Money Blimp appear in a flashback in the 1978 story Captured in Bananaland.