I created this, after getting inspired by this gun sounds tutorial.

What I did was (In Audacity terms):

1. Record letting air out of a balloon

2. Fade in

3. Reverse

4. Change speed (50%)

5. Slide Time Scale/Pitch Shift (Initial tempo: 0%, Final tempo: 92%, initial shift: 0, final shift: 0, no DTS) about 5 times

6. Change tempo (50%)

7. Normalize (-0.5)

In Daft Punk terms that would have been: Fade it, flip it, slow it, shift it, slow it, normalize and save it.