Roy kept one of the mogwai named Earl that spawned from Gizmo to run some tests on it and after taking a blood sample, Earl the mogwai is at first friendly towards Roy, but after Roy conducts a series of blood tests on Earl, Earl changes and wants revenge on him. One night after conducting some more blood tests, he leaves for home and leaves the caged Earl at the school. Earl, who lusts for revenge, manages to grab a sandwich off the table and pulls it towards itself before devouring it after midnight. When Roy arrives the next morning, Earl is already in his cocoon form and is undergoing a metamorphosis.
After the cocoon hatches, Roy wants to see the metamorphosed creature and tries to coax him out of hiding underneath a desk with a candy bar. Earl, now a gremlin, eats the candy bar and proceeds to start biting Roy's hand. When Billy arrives, he comes in and finds that Roy has a syringe jabbed on his buttocks and is possibly dead on the floor, partially underneath the desk.