In this Halloween episode, an experiment that can morph into a person's worst fear is discovered. It is revealed that Mertle, Elena, Teresa and Yuki's worst fear is seeing Lilo without her head; Moses' worst fear is spiders; Lilo's worst fear is clowns; Stitch's worst fear is water (or of drowning); Nani's worst fear is losing Lilo (especially hearing Cobra Bubbles say he came to take Lilo away); Jumba's worst fear is his ex-wife; and Pleakley's worst fear is his mother.
- Moral: If you face your fears, you'll likely get over them.
- Spooky bears a great resemblance to Oogie Boogie from The Nightmare Before Christmas.
- Spooky has glowing, olive-green eyes instead of black ones like most of the other experiments.
- Jumba also referred to Spooky as "X300" and mentioned that his impression of Jumba's ex-wife is frightening.
- Unlike most experiments, Spooky's number is pronounced as a whole number ("three hundred") instead of three individual digits (which in his case would have been "three-oh-oh") as per the norm for the experiments.
- Lilo revealed that she is afraid of broccoli and clowns, the latter being her worst fear.
- Mertle shows a little compassion when she admits that Lilo should attend the Halloween party and also confesses that Lilo was right about her, Elena, Teresa and Yuki's costumes being too boring. Regardless, Yuki points out that Mertle forced them to do this in the first place.
- Stitch spit out a lemon, saying, "Ew, organic!", implying he might not like lemons.
- However, in "Swapper", he drank a whole bowl of lemonade (albeit modified by Jumba to cause those who drink it to temporarily change colors) without expressing any disgust, which would contradict this supposed dislike of lemons. It could be that either Stitch doesn't like organically-grown foods (grown using natural fertilizers; Stitch's heightened senses might have the unintended side effect of him tasting even the tiniest amounts of manure residue), he doesn't like the taste of unsweetened lemons or lemon juice, or him spitting out the organic lemon was nothing more than a simple joke.
- Nani is the only character to have an emotional fear, as opposed to an irrational one.
- It would seem that, according to Spooky's impression of Jumba's ex-wife, Jumba's species naturally has poor grammar with regards to English.
- Lilo and Stitch use the song "Aloha `Oe" from the original movie as a coping tactic to overcome their worst fears.
- Gantu, Reuben and Hämsterviel do not appear in this episode.
- In spring 2004, Disney Channel held an online poll that asked viewers for their favorite experiments and episodes from Season 1 of the series. According to the top 10 results of that poll, "Spooky" was the #4 most popular episode and experiment.