Like many nocturnal creatures, mogwai and gremlins are incredibly photosensitive. Yet even the eyeless, subterranean olm salamander merely changes color if exposed to direct sunlight. Ultraviolet (UV) rays can kill most bacteria, but such a reaction is unheard of in larger organisms.
Except for the mogwai/gremlin species, of course. Let in a little sunlight and they immediately fester and melt into a grotesque green sludge.
For most people, the only real comparison is the reaction we see when a particularly morbid (or curious) child pours salt on a slug: The salt crystals draw vital moisture out of the slimy creature, effectively dehydrating it to death. But that's not what happens when a gremlin melts.
If you'll think back to the mogwai's metamorphosis into gremlinhood, you'll remember the process closely resembles a caterpillar's transformation into a butterfly. Once cocooned in their chrysalises, both caterpillars and mogwai produce an enzyme that breaks their bodies down into a rich bath of imaginal cells. Those cells ultimately reconstitute the creature's metamorphosed form.
When exposed to direct sunlight, the mogwai/gremlin body produces this exact enzyme, essentially causing the body to digest itself -- only outside the safety of the chrysalis. Needless to say, it's quite an excruciating mode of death for a gremlin or mogwai, especially since the creature remains conscious even after the process reduces it to a pile of slime, bones and brain.
Scientists are still unclear why this disgusting physical reaction takes place, but most signs point to it being a congenital mutation common to all mogwai and gremlins. Other aspects of the creature's life cycle are dependent on solar activity. In fact, as we'll explore on the next page, the position of the sun partially triggers a mogwai's remarkable metamorphosis.