Snowball is a WordPress plugin that serves as an additional editor inside your admin. Inside Snowball you can build longform articles that sit alongside the rest of the content on your site.

snowball-editor

Have an idea for a special post with full-width images, pull quotes, and other enhanced features? Install Snowball and get to writing and building your article.

A powerful WordPress plugin that makes it possible for anyone to create immersive longform articles for the web

Source: Snowball | A powerful WordPress plugin for creating immersive longform articles for the web