William "Billy" Peltzer is the deuteragonist and main human protagonist of the Gremlins franchise. He's a young man whose father gives him a Mowgai, Gizmo with a set of rules such as not feeding him after midnight, no no direct sunlight and try not to get water on him. However, Billy and his friend accidentally gets drops of water on Gizmo, resulting in him spawning more Mowgai. One day, Billy is tricked to feeding Gizmo's offspring after midnight when they sabotage his clock, resulting in the creation of the Gremlins. Now he and his crush, Kate with to defeat the Gremlins once and for all.
In the sequel, Billy is reunited with Gizmo as they work together to defeat a new batch of Gremlins and stop them from wreaking havoc on New York City.