The first trailer for “Aquaman” was just unveiled at Comic-Con, with glimpses of an epic underwater battle between combatants riding sharks versus those on seahorses.

Taking a page from “Harry Potter,” young Arthur Curry finds he can communicate with sharks, rays,  and other sea creatures in a visit to the aquarium.

He grows up to be Aquaman (Jason Momoa), who learns he’s half-human and half Atlantean — and that his underground city needs him.

Besides glimpses of a beautiful city under the ocean, we also see sea turtles, sharks battling it out with crustaceans and … a sheep?

And in a scene where Aquaman follows flame-haired Atlantean Mera (Amber Heard) in jumping out of a plane without a parachute, a sheep who’s along for the ride appears surprised at the turn of events.

Let’s hope no one feeds the sheep to the sharks!

“Aquaman” opens December 21, 2018.