Buffy asks Xander "You and bug people, what's up with that?" to which he replies "He was no Praying Mantis Lady" - refering to the substitute teacher that seduced Xander, but was in reality a praying mantis.
Xander mentions if it weren't for Buffy he wouldn't have a head. Buffy saved Xander from the praying mantis that was to bite Xander's head off in "Teacher's Pet"
Cordelia says that Xander has always been attracted to monster, refering to the events of "Teacher's Pet" and "Inca Mummy Girl" where Xander was attracted to a monster without knowing it