Xander says in Reptile Boy, “Ok boots. Start a-walkin’.” This is a reference to the 1966 Nancy Sinatra song “These Boots Are Made For Walkin’”.

In Reptile Boy, Tom says, “Anyway, the Hulk is gone, so you don’t have to dance with me.” This is a reference to Marvel Comics’ angry superhero the Incredible Hulk.

In Reptile Boy, Willow makes a good point on noticing Angel’s lack of reflection. How does he shave? Perhaps his hair doesn’t grow? We also learn in this episode that vampires have an amazing ability to smell blood.

In Reptile Boy, Buffy and Angel agree to go for coffee, and attempt to do this in Halloween. Buffy makes a big show that going for coffee is an important date-like event in season five’s I Was Made to Love You when she meets Ben and they have a painfully …

David Greenwalt, who wrote the episode Reptile Boy, thought he made up the name Machida, but found the name (though spelled differently) is a brand of tools.

Drinking alcohol in Buffy the Vampire Slayer has always been frowned upon, though the rules were relaxed slightly as the Scoobies got older. The general rule is: if you have a drink, something bad is going to happen to you. Here are some examples of this rule:
In Teacher’s Pet, …

The cemetery which Callie runs through at the beginning of Reptile Boy is the same one used in the season six episode Entropy where the nerds ride their ATVs, chasing a vampire. The graveyard features tombstones reading “Mother” and “Dad”. Nice and vague.

In Reptile Boy, both Richard (one of the college guys) and Callie (the kidnapped girl) have the last name Anderson. The name was also used in The Pack: the family whose car was attacked by hyena-people were named Anderson.

Jonathan, who was introduced in the previous episode (Inca Mummy Girl), re-appears at the end of Reptile Boy as Cordelia’s date and is named for the first time.

Ampata’s surname - Gutierrez - is the same as Joss Whedon’s personal assistant: Diego Gutierrez. According to the original script, Ampata’s surname was originally going to be Duarte.

Both Nicholas Brendon (Xander), and Ara Celi (Ampata), had to eat up to ten twinkies each for the scene in when they are eating lunch in Inca Mummy Girl.

Inca Mummy Girl was the first episode since Nightmares which does not feature the character Angel, even though he is credited in the opening titles.

Jason Hall played Devon, the lead singer of Oz’s band Dingoes Ate My Baby. British fans might be interested (or appalled) to know that Jason appeared in an episode of the British TV sitcom Birds of a Feather in 1992, playing a gas man. He also appeared in an episode …

According to the sign Spike passed on the way into Sunnydale in School Hard, the town’s population was 38,500. Interestingly, the population was the same in season three’s Lover’s Walk. Either nobody had changed the sign or people have babies rapidly in the town because people sure have been dying.

Spike says to Angel in School Hard, “Man, I can’t believe this. You Uncle Tom!” This is a reference to the 1852 novel Uncle Tom’s Cabin by Harriet Beecher Stowe (1811-1896).