Balloon

You can check your answer here.

Idioms can be misleading. :cry:
(Voted first, then checked it out.)

This one certainly is. ;-)

I got this one right, but I was thinking about a weather balloon rising in unstable weather conditions (I.E. about to storm). However, it comes from WWI when balloons were launched to signal artillery strikes.

I am so stupid! I wanted to be fast :roll: