Since I played Sapphire I've always wondered what the hell the Nebula was and why it, like other unknown units in campaign, were never added to the player's blueprints.
Here's a picture I took when I captured the Nebula in the Sapphire campaign.
https://gyazo.com/707b472502cfa0f4b1c0bed08e14723dIt's cut off because only when I left I realized I only took portion pictures lol.
It has a large shield, is generally brittle, and produces some kind of fighters similar to the Reef.