[1] The episode was written by co-executive producer David Greenwalt and directed by Bruce Seth Green A substitute teacher's infatuation with Xander is flattering to the lovesick teen, but alarming to Buffy.
[2] One evening in the Bronze, Xander (Nicholas Brendon) saves Buffy (Sarah Michelle Gellar) from a menacing vampire.
When Buffy and Willow (Alyson Hannigan) arrive, Xander puts his arms around both girls to buff up his reputation.
The substitute biology teacher, Natalie French (Musetta Vander), shows up and turns every boy's head.
French suggests making model egg sacs for the upcoming science fair and asks the class for help.
This makes her late for the pop quiz that Miss French gives the class — a test where she tells Xander the answer to a question.
Xander wakes up in a cage next to Blayne, who tells him how she mates like a praying mantis, biting off men's heads in the process.
Buffy tells Giles to record bat sonar — a sound that damages the insect's nervous system — while Ms. French chooses Xander as her next victim.
Buffy, Willow, and Giles arrive at the She-Mantis' registered address, where they find an old woman (Jean Speegle Howard) who is actually named Ms. French and has been retired from teaching since 1972.
After science class, Buffy places Dr. Gregory's glasses in his jacket, which is still hanging in the classroom closet, oblivious to the eggs attached to the bottom of a shelf — or the fact that one is hatching.
[1] Vox ranked it at #132 on their "Every Episode Ranked From Worst to Best" list of all 144 episodes (to mark the 20th anniversary of the show), writing, "By 1997, the student/teacher love affair was already a well-worn teen soap trope, and "Teacher's Pet"'s twist of having the teacher be a literal predator is only mildly clever."
However, "the core Scooby dynamics have really started to gel: The scene where Giles corrals the kids into researching the two monsters decapitating and shredding their way through Sunnydale ("Fork Guy doesn't do heads," Buffy notes) hits all the classic beats ...
[5] DVD Talk's Phillip Duncan was somewhat disappointed with the episode, calling it a "by-the-book monster thriller set in the high school".
[6] Rolling Stone ranked "Teachers Pet" at #140 on their "Every Episode Ranked From Worst to Best" list, calling Xander a "character who would often be the 'damsel in distress' figure," and writing that the episode "isn't anything to write home about though, with a passingly clever take on the teacher/student love affair, with the teacher here being quite literally a predator.