In the library, Giles consults the Malleus Maleficarum, an actual historical text on Witchcraft. Written in the late 15th century it was essentially a how to manual on how to identify, capture and kill witches, demons and other foul creatures. Even for those times it was considered extreme and vile and was banned by the pope in the early 16th century. Unfortunately, it was written the same time that the printing press was taking off in Europe and it became the 2nd most popular book in Europe for decades. It is credited with being one of the major causes of the witch hunts that swept Europe. It is also the source of many of the stereotypes of redheads, which were described in the book as Vampire demons which had no souls and could not walk in the daylight. The book was so prevalent that mothers were known to drown newborn babies if they had red hair, and some towns even purged all redheads, often by burning at the stake.
The picture used in the book to show the consequences of primals is an illustration from Dante's Inferno by French artist Gustave Doré.
During the dodgeball game, the pack defeats the opposing team easily, leaving Buffy as the last one standing. But, instead of attacking her, they turn on Lance, their own teammate, showing how hyenas will generally avoid confronting powerful animals and prey on the weak instead.
Buffy says that "Apparently Noah didn't want Hyenas on the ark because he thought they were an evil, impure mixture of dogs and cats." Hyenas are cats or at least, they're feliform, rather than caniform. They're related to cats, weasels, ferrets, and mongooses. Their doggy shape and pack behavior is convergent evolution.
The hyena lore featured is possibly based on the crocotta of Ethiopian legend. It's a wolf-like creature whose name was used for the scientific name of the spotted hyena (Crocuta crocuta). It is said to imitate human voices and call out to people, like the hyenas call Willow's name.