The first of SpongeBob’s family to foray into time was Squidward, whose accidental
cryofreeze took him two millennia into the future. Of course, even
primitive sponges know that that was not actual time travel, but future-SpongeTrons point
the six-limbed cephalopod to a time machine that took him on two actual time travel trips
before returning him to his own time. No, we don’t know whether one of the future
SpongeTrons is SB-129, but we do note that the production code for this episode was 2515-129.
— Inmate Jan