It's Pony S02 E15a 'Hot Tub Brine Machine' Production Animatic

When Annie tells Pony he needs to wait 30 minutes before they can get ice cream, he decides he'll pickle himself to travel forward in time. When he comes out of the brine, he thinks that decades have passed.

Written by Magda Liolis and Bob Mittenthal
Directed by Ant Blades
Storyboard by Hugh La Terriere