They are the word "alone" that will appear in many different ways. They all only say the word "alone."
Role in episode
They are heard after Squidward, who is in the end of the time period called Nowhere, says "I may have finally found a place where I can be all... alone!" They echo the word 'alone' many times in various different voices (including that of the French narrator), depicting a very strange alternate-reality to which Squidward had traveled to.
Squidward soon panicked after hearing the echoes, thinking someone was after him. It is possible that the alone echoes were from Bikini Bottom residents from the future who used the time machine and ended up in Nowhere years before Squidward had. It could also be possible that the alone group is actually just an echo of Squidward's voice, which seems logical as Nowhere is a small but infinitely looping space (as seen when Squidward attempts to escape from the realm by running out of it, but ends up running in a never-ending loop).
- In total, the word "alone" is shown 13 times in this group.
- The word alone is heard 16 times during the scene.
- The words all have different fonts, shapes, and sizes.
- When Squidward appeared in the past, his time machine was with him, but for some reason, when Squidward visits the Realm of Nothingness, he's seen without it. The realm exists on top of the time machine, which didn't happen previously.