More background pony. A personal favourite of mine (mainly for her colour scheme and cutie mark - I've always been a sucker for dolphins), Sea Swirl also known as Sea Foam. The moment I read her blind bag toy description on the Friendship is Magic wiki I wanted to draw her underwater, so this is the result.
Yes. I know her mouth is open and she probably wouldn't be able to breathe - my logic dictates that her magic can let her breathe underwater.