Elastico is a very playful, fun-loving experiment and treats just about anything like a game. He loves entertaining folks, sometimes breaking the rules for his own fun. Being a natural contortionist, he amuses himself by stretching his body into fun shapes or using them to pull little stunts or jokes on others. He can be a bit of a prankster, as he enjoys fooling around and teasing his enemies, often irritating them. Despite this, he can be very jumpy in immediate danger or if someone is trying to catch him. Also, he loves both of his families (his circus family and his ʻohana with Lilo, Stitch, and the other experiments) very much.
Elastico is generally very friendly and affectionate towards others. The one thing he dislikes more than anything is being grabbed or restrained, with the exception of hugs. He is also very terrified of Gantu, screaming every time he sees him and grabbing onto Stitch's head when Gantu approaches. This is quite reasonable due to the fact that Elastico has been grabbed, choked, netted, kidnapped, pulled, squeezed, blasted and shackled by Gantu. Despite this, he seems to have gotten over his fear by "Checkers", as he was seen bravely rebelling against Gantu.
Experiment 345 was the 345th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to distract enemies by performing tricks with his elastic body. 345 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.
All of the experiment pods were released and scattered across the island of Kauai.
At an unknown point after this, Experiment 345 was activated.
345 eventually found his way to an international circus, where he was taken in and named Elastico by the troupe's ringmaster.
A news article with Elastico's picture in it was almost used as a sandwich wrapper by Experiment 625. When Gantu noticed the article on his ship, he snatched it and briefly read the section, then headed off to the circus to capture Elastico.
Meanwhile, Lilo was engrossed in a new hula dance, but ignored Stitch when he offered to help her. Stitch later noticed Elastico riding atop a circus van and followed him to the circus. There, Stitch disguised himself as a clown and tried to capture Elastico, but the latter teased Stitch and turned the whole chase into a game. Eventually, Elastico calmed down when Stitch grabbed him and called him "cousin."
The entire audience began cheering for Stitch, who was then praised by Elastico's ringmaster. However, at that moment, Gantu barged in, strangled Elastico, and stuffed him into a net before fleeing.
Stitch revealed that Gantu kidnapped Elastico, much to the ringmaster's dismay. He then mentioned how Stitch stole the show with his incredible stunts, and even invited him to perform in Elastico's stead, to which Stitch happily accepted. He later met the circus troupe and signed a contract permitting him to travel with the circus.
Meanwhile, Gantu tried to teleport Elastico to Hämsterviel, but the experiment put up quite a fight and proved difficult for Gantu to control. Reuben wagered a sandwich on the ordeal, though Gantu eventually disabled Elastico by blasting him and put him in shackles. However, he stretched out of the cuffs and under the teleport chamber just before the transfer could be completed.
Elastico somehow packaged himself and then shipped himself back to the circus, reuniting with his ringmaster. Lilo later found out that Stitch ran away with the circus, so she paid him a visit and attempted to make amends. Just then, Gantu attacked and tried to take Elastico back, but was thwarted by Lilo and Stitch, along with the entire circus troupe.
While Elastico's family prepared for their next show in Las Vegas, Lilo and Stitch made up. When the ringmaster saw that Stitch had a family of his own, the former voided the contract and let Stitch be with his ʻohana. After Stitch said his goodbyes, he and Lilo decided that Elastico's one true place was to stay with the circus.
In "Remmy", Elastico was one of the experiments in Lilo's dream.
The first 624 experiments, including Elastico, were rounded up by Leroy and taken to a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben and Gantu arrived before the experiments could be destroyed.
Elastico participated in the following battle between the experiments and the Leroy clones by strangling Leroys with his elastic body.
However, the Leroys soon gained the upper hand in the battle, but were defeated when Lilo, Stitch, Reuben and several other experiments performed the song "Aloha ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe. Elastico joins them for the song by playing the trombone.
Elastico made an appearance in the Stitch! anime where Hämsterviel gave him the additional power to transform things into circus-related items and animals, such as dogs, monkeys, elephants, seals, etc., in order to turn Stitch into a harmless little puppy, thus making him easier to capture. However, Yuna was turned into a dog by mistake, and Stitch didn't realize it was actually her until he found her in a circus tent being tortured to do tricks for the circus.
- Elastico is one of the ten known experiments named by someone other than Lilo, the other nine being Gigi, Yaarp, Hammerface, Heat, Thresher, Plasmoid, Morpholomew, Shrink, and Leroy.
- Elastico's name, primary function, and one true place are revealed, but his official number was never revealed in his episode.
- Despite being very flexible, Elastico couldn't seem to escape the net he was captured in.
- Elastico's pod color is green.
- Elastico is described by the experiment computer screen as, "Experiment 345. Primary function: Distraction of hostile forces."
- Elastico's head appears in the online game Jumba's Lab.