Acrobatic Slugs?

Has anyone else witnessed this bizarre phenomena?




This dude was not only just hanging there on a string (ew) of his slime (ew!), he was blowing around in the wind and the stuff was bouncing like a bungee cord! I have seen this twice in my yard so far this year, once hanging from the wisteria, and once from a paper birch. I knew that the slugs were out to get me but wow - paratroopers?