Jellig

Jellig is a fictional gel-like material described in certain speculative fiction works and puzzle communities. The name combines elements of "gel" and "jelly" to suggest its soft, pliable nature. In most renderings, jellig exists as a translucent, elastic substance that can be shaped at room temperature and returns to its original form after minor deformations.

Physical properties vary by depiction, but common features include high viscoelasticity, self-healing after rupture, and light diffusion that gives a faint glow. Some versions describe jellig as thermally responsive, becoming more rigid at higher temperatures and softer when cooled; others portray it as nearly incompressible and highly compliant.

Production and sources also vary. In-world narratives frequently attribute jellig to bioengineered cultures or to exudates from deep-sea organisms, harvested via noninvasive methods. It is sometimes described as biodegradable, though certain subtypes are depicted as having long-lived sensory networks embedded within the gel matrix.

Applications in fiction and games include soft robotics, biocompatible scaffolds for hypothetical organ growth, and flexible electronics. Artists and designers use jellig to create sculpture and architectural elements that can be reshaped without tools.

Origin of the term remains uncertain in-universe, but most scholars trace it to a blend of jelly and gel terms used by early researchers who first documented the substance in field notes.