Mo Slowmography is a really fun app. The first time I tried it was the day the "Gravity Waves" were discovered, so I played around it with, which led to this awesome Vine: https://vine.co/v/inOiZZz6pvm
TL;DR you can make really cool slow-motion videos and GIFs, and choose the coolest after effects. Oh, and another Vine I made was at the Blab office and messing around with the Shkreli mask we made (as joke, we were trying to see if he notices) but notice the cool after affect of how it fades out: https://vine.co/v/inwEu6PPenJ
I believe the makers are making the Pro version free for the day so check it out and ask @tamasszakal anything! cc @everyday_slowmo
VC Puzzle