When Billy's friend Pete Fountaine spilled water on Gizmo, the first batch was born. They were rude and mean to Gizmo, bullying him and doing whatever they pleased. One night, they stopped Billy's clock at 11 so they could eat past midnight. The next morning, they metamorphosized into disgusting cocoons.
When Lynn Peltzer saw that they hatched, Billy called her and told her about it, whereupon they cut the phone connection and started a record player, which drew Lynn downstairs and into the kitchen, where she met three of them and managed to kill them all (as stated in the DVD commentary, Lynn was initially supposed to be decapitated by the gremlins, but this had a very negative response from the rest of the cast, and was never made).
Afterwards, she wandered into the living room and was ambushed by a fourth Gremlin hiding in a Christmas Tree and was almost killed, but Billy arrived and chopped it's head off. Stripe, the last living one of the batch, then showed up and smashed his way out through a window and rushed out into the night.
After finding out about the new mogwais, Billy took a mogwai to Mr. Hanson his old schoolteacher and showed him how they multiplied with water. He gave the newly spawned mogwai, Earl, to Mr. Hanson for testing.
- In the Hub (now Discovery Family) airing of Gremlins, most of their deaths were shortened, such as The Plate-Throwing Gremlin whereas when the button is pressed to chop it up, it cuts to the part when Lynn Peltzer was gasping behind the wall. Then she turned around and turned it off.
- In the part where Lynn fights the First Batch, there are 5 Gremlins, yet in the novel, there's only 4, because one died prior to becoming a Gremlin. This could be a retcon, but there's a possibility that 6 Gremlins were spawned from Gizmo, yet only 5 of them were noticed by Billy and his family.