These aliens appear at the end of the episode "SpongeHenge" when they arrived in Bikini Bottom over a thousand years in the future, looking at the stone sculptures that were made by SpongeBob thousands of years before.
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 short legs, travel in rocket-powered pods, and carry their cameras in their mouths. Their voice can be described as being monotone and female.
Role in episode
In the future, the aliens gather around the stone sculptures that SpongeBob made in his likeness, but they do not 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 tune.
They live in the 51st century (5017), which is 1,000 years after the future in the episode "SB-129" (4017).