Spike, A.K.A. Experiment 319, is an illegal genetic experiment created by Jumba Jookiba. He is designed to fire spines that make his victims goofy by decreasing any hit victim's intelligence by 99%, leaving them only 1% clever for the next 48 hours. His one true place is in Pleakley's E.A.R.W.A.X. group, hugging and thus taming truant experiments, after he is given protective armor to cover his silliness-inducing spines. He is voiced by Frank Welker.
He was activated when a water bottle spilled on an outdoor stage and it leaked onto his pod. His effects wear off after 48 hours. When Lilo discovers Mertle cheating in the Ohana-Rama contest by getting the answers from Teresa, she uses 319 on Teresa to have her give Mertle completely silly answers. His episode also features these experiments: 032 Fibber, 110 Squeak, 149 Bonnie, 150 Clyde, 199 Nosy, 523 Slushy, 613 Yaarp, and 619 Splodyhead.
Spike is shown to be very troublesome, as his spines pose a dangerous threat to anyone pricked by them. He also has a feisty side to him and will attack any target, even if he's outnumbered. However, he is not afraid to show emotion as seen when he cried noisy tears while Pleakley hugged him during the E.A.R.W.A.X. session. This not only rehabilitated Spike, but also motivated him to be a hugging therapist and follow Pleakley's hugging-and-crying method.
Spike is a large dark blue porcupine-like experiment with huge white-tipped spines on his tail, back, front legs and head, a red nose, large black eyes, black claws and a long tail.
Spike can fire his spines like darts at targets. His quills also contain a venom that increases the victim's goofiness by 99% when struck, leaving them only 1% clever. He is able to roll into a ball and launch his spikes while spinning at incredibly high speeds.
Spike is emotionally susceptible to hugging therapy, and the effect of his goofiness-inducing spines only lasts for 48 hours. Also, only Jumba himself is immune to Spike's silliness-inducing quills, due to already being a genius.
Spike made an appearance in Season 2 of the Stitch! anime along with Hammerface, Babyfier, Link, and Woody. It is revealed that Hämsterviel reverted these experiments to evil using a recording of Angel's song, thus enabling them to wreak havoc on the island. In another episode, Spike was also used by Hämsterviel to try to sabotage a quiz competition. His abilities were modified in this episode so that he only reduces the victim's intelligence, and it can be magnified by squeezing his nose. It is shown that he has the ability to roll into a ball and launch his spikes while spinning at incredibly high speeds.
- Dr. Gladys Okra, Spike's first victim, bears a striking resemblance to Oprah Winfrey.
- When Jumba got pricked by Spike, he did not act stupid since he was already a genius even by 1%, indicating that he is the only one immune to Spike's goofiness effects, though he still felt the pain from the spines alone.
- Spike is clearly a porcupine-like experiment, but unlike him, real-life porcupines cannot throw/shoot their quills, nor are their spines poisonous.
- Spike is one of the six known experiments to be rehabilitated by someone other than Lilo and Stitch, the other five being Gigi, Elastico, Yaarp, Frenchfry, and Snooty.
- Spike's pod color is yellow.
- Spike is described by the experiment computer screen as, "Experiment 319. Primary function: Makes victims act goofy and stupid".
- In the English dub of the Stitch! anime episode "Link-age", Reuben states that Spike's favorite type of sandwich is shish kebab euro.