This fucking episode. It may just be another episode to you all, but I have a dark history with this shit. Ever since I first saw "SB-129" as a kid, I was scared shit-less of it. Only a few years ago did I get over it. There are 3 parts of the episode in particular that got me spooked:
1. The title card. Just the way the text wobbles around floats, the robotic voice, and the boop noises used to freak me out. In fact, before I knew about TV Guide, I would always run out of the room when the theme song came on in fear of it being this episode.

2. The main thing that stuck in my head and kept me up the night I first saw it is the image of Squidward's frozen face immediately after the "2000 years later" title card.

3. The part that drove home the point of this being a fucked up episode as a kid was prehistoric Patrick's teeth (probably the actual scariest part now).

It's a shame I never saw this episode much, because I think it's one of the best. I'm just glad I never saw "Face Freeze!" or "House Fancy" as a child.