Buffy first encountered the vampire Gorch brothers while shopping
with her mother. She intervened just as Lyle was about to attack
a woman playing pinball. He ran off, and later Giles discovered
that the brothers were infamous for massacring an entire Mexican
village, in 1886, before they became vampires.
The brothers' arrival in Sunnydale coincided with the threat from
the Bezoar, a prehistoric parasite creature whose eggs were turning
townsfolk into zombies. The brothers ended up in the school boiler
room, where the Bezoar was lurking, serviced by his minions. Tector
was dragged into the pit, and eaten. Lyle ran away as Buffy attacked
and killed the creature with a pickaxe, freeing the enslaved humans.