You may have noticed that on the Fifth Dawn artifact destruction card Tel-Jilad Justice, something has been crunched. That's an aerophin. What's an aerophin?
The aerophin is a species of flying artifact creature with a dolphinlike body and a translucent sphere for a head. They can fly fast and emit a powerful energy bolt from their bubble-shaped crania.
Here's a concept sketch from the Mirrodin block style guide (illustration by Sam Wood).
The blue-aligned race on Mirrodin, the Vedalken, use aerophins as servants. Hoverguards (well-represented on Mirrodin block cards -- Somber Hoverguard, Hoverguard Observer, and Hoverguard Sweepers for example) serve the Vedalken synod as "heavy artillery" on defense. In contrast, aerophins are fast, light, and aggressive. Because they can travel great distances quickly, the Vedalken send them to do their remote dirty work.
Here's a blown-up look at the art of Tel-Jilad Justice (illustration by Alex Horley-Orlandelli), so you can see one aerophin that won't be running any more Vedalken errands.