The Mogwai is a rare sentient being as it is a furry, cute, very curious creature. wikipedia Mogwai appear to originate from Western Asia. The word "Mogwai" in Cantonese translates literally as "monster". Mogwai appear as small rodents, resembling anthropomorphic hamsters or guinea pigs and are generally similar in appearance, but can have their own individual features. There appear to be two types of Mogwai, gentle types, and the more aggressive and troublesome type. ‘’wikipedia’’
There are "rules" for keeping a mogwai; "Don't get him wet" as, when exposed to water, it immediately reproduces more of its kind asexually by budding from its back; "Keep him away from bright lights….especially sunlight" Sunlight will kill a mogwai and bright light is known to hurt it; and the most important rule "Don't ever feed him after midnight" as if it eats food after midnight, it will create a cocoon, going through changes and become a ferocious, reptilian monster called a gremlin. ‘’wikipedia’’

Gremlins are tall, scaly-skinned creatures with large ears resembling bat wings, have fanged mouths, and a seemingly instinctive desire to cause havoc at the cost of humanity. Gremlins may keep their physical features from when they were Mogwai. Gremlins are very anarchic creatures, although some can seemingly be doing it for fun, whilst others like Stripe are more deliberately sadistic and violent. Gremlins also display little care for their own species or others, willing to shoot their own kind to get a laugh out of it. Gremlins can be killed particularly easily. ‘’wikipedia’’
They are governed by the first two rules of owning a mogwai; however, eating after midnight has no effect on them, and any spawn they produce immediately start out as gremlins. Mogwai creatures are mean-spirited and mischievous, with a few rare exceptions.

The level of maliciousness in the personality of mogwai and gremlins vary. Some have been observed as exceedingly violent and show great delight in hurting others. While other just delight in scaring people, causing hijinks, and general destruction. All mogwai are energetic and extremely curious, the latter quality often getting them into trouble.

Mogwai/ gremlins are also pack minded, following a leader who is dominant but also has a quality that differentiates them from the others of their kind. These leaders appear to have a strip of fur the others don't, and are more violent and more dominant than their brethren. ‘’wikipedia’’

It is thought that Mogwai are the result of genetic manipulations by an alien scientist to create a pet for children, but turned out mischievous and/or evil and the transformation mogwai can go through being totally unintended. Only one in a thousand are gentle, and as a result is hated by his brethren. Also, this previously mentioned mogwai is effectively immortal. As Gizmo is gentle, and has a long list of historical figures that have owned him, it is clear that he is this mogwai type. If this mogwai eats after midnight though, he will lose his longevity, becoming a typical gremlin. ‘’wikipedia’’ - //edited from Wikipedia