Trevor Spengler, played by Finn Wolfhard, is a character in the film Ghostbusters: Afterlife.
After Callie is evicted, she moves the family to Egon's house in Summerville, Oklahoma. Trevor isn't happy about the move until he spots Lucky Domingo working at a fast food restaurant and applies for a job so he can work with her.
Trevor is mechanically inclined, shown tending to Callie's car during the move. He also discovers an abandoned Ecto-1, and manages to get it running again, with a little help from an unseen ghost (later revealed to be his grandfather, Egon). While joyriding in Ecto-1, he finds Phoebe and her friend Podcast walking on the highway. He picks them up and they find a strange ghost Podcast named Muncher. Together, they manage to capture the ghost but on the way home, they are arrested for damage to public property among other things.
Eventually after being released from jail, the Temple of Gozer is activated and he takes the Ecto-1 from the impound lot and join with Phoebe, Podcast, and Lucky to attempt to trap Gozer. With the help of Peter Venkman, Ray Stantz, Winston Zeddemore, and the ghost of Egon, they manage to stop Gozer again.