Creature:Skyfish

Skyfish are a species of invertebrates indigenous to the planet Tropha. They fly at speeds exceeding 100 mph, which makes them difficult to spot by many species. Skyfish are born in and generally inhabit the stratosphere, and spend their entire lives in flight; should one end up on the ground they are extremely vulnerable, and often will have difficulty getting back into the air as they do not possess limbs to allow quick movement to lead up to flight.

Sporepedia Description
"The Skyfish originated on Tropha, the homeworld of the Permitted. Extremely fast flyers, they streak across the sky, barely visible to the naked eye. They infest many Permitted ships, and are accidentally transferred to many worlds by them, including Earth."

Trivia

 * Skyfish are intended to be a hint that flying rods on Earth are in fact a species accidentally seeded by the Permitted during their times there.