On October 28th, 2015 Snapchat updated their app with the Slo-Mo or Slow Motion video option. You now have the ability to take a video, swipe to the right or left and find the filters available. The filter for the slow motion looks like this:
It looks like a snail. It is extremely hard to screenshot this icon as it goes away very quickly. I will create a YouTube video on how to do it as well.