They are light purple, wrinkly and tear shaped, and have an extra eye on their forehead that is a different color than the other two. They have four legs, travel in rocket-powered pods, and carry their cameras in their mouths.
In "SpongeHenge," in the future, the aliens gather around the stone sculptures that SpongeBob made, but they don't know why they were created or who made them. They only know that the genius of their design has caused the annual migration of jellyfish to their wondrous tune.
They live in the 51st century, which is 1000 years after the future in the episode "SB-129."