You Jelly?

Shining and Twilight go surfing. Then they suddenly learn why they have the whole beach to themselves.

Twilight Sparkle is on summer break from Princess Celestia's School for Gifted Unicorns. It's the last summer before Shining Armor ships out to the Royal Guard academy. They decide to go to the Thestralian Gold Coast to engage in watersports... Which is to say some world-class surfing!
And also the other kind when they get stung by jellyfish.