In Crush, Spike refers to the events of Blood Ties when he helped Buffy fight Glory in the hospital. Another reference to that episode is that Willow is still getting headaches because of the teleportation spell she did on Glory.

In Crush, Harmony says that the only girl she’d consider a threesome with is blonde Charlize Theron, who won an Oscar in 2004 for her role in Monster.

Spike asks Buffy in Crush if she likes The Ramones. They were a punk band in the 1970s. Spike sings some of “I Wanna Be Sedated,” from The Ramones’ 1978 album ‘Road to Ruin’.

In Crush, Willow, Tara and Buffy discuss The Hunchback of Notre Dame, a novel by Victor Hugo. Buffy mentions singing gargoyles, which is a reference to the musical Disney version of the novel, made in 1996.

In Crush, Harmony calls Drusilla “Morticia”, who was the matriarch in The Addam’s Family. Mercedes McNab (who plays Harmony) appeared as the girl scout Amanda Buckman in The Addam’s Family and Addam’s Family Values.

Sunnydale’s train station is seen for the first and last time in Crush. We discover it’s the last train station on the line.

Jennifer Bergman, who played the girl Drusilla killed in the Bronze in Crush, is also a visual effects producer. She has worked on Blade, Firestorm, Broken Arrow and Mighty Morphin’ Power Rangers.

The episode Crush is last time we see Drusilla in person on the show, though we see her again in flashbacks and as The First.

Mercedes McNab played Harmony for the final time on Buffy in Crush. Harmony then moved on to L.A., after her heart was broken by Spike for (nearly) the last time.

Spike’s pet name for Dawn is “Niblet”, heard in Blood Ties, Seeing Red, Beneath You and Lies My Parents Told Me.

Glory says the Key is pure green energy in Blood Ties. In Tough Love, Tara reveals to Glory that Dawn is the Key by saying she’s a beautiful green light.

In Blood Ties, Buffy asks the Scoobies if they looked for Dawn at the carousel, when she goes missing. This is most likely the same carousel that Riley took her to in Shadow. Dawn told Riley that Joyce had rented out the carousel for Dawn’s birthday just after they moved …

Ben beat up Glory’s minion Jinx in Checkpoint as a message to the hellgod that he wouldn’t co-operate with her. In Blood Ties, Jinx’s face was still injured from this, and Ben reminded him why. In Forever, Ben told Jinx, “you’re more fun when I hit you”.

In Blood Ties, Glory recognises Dawn from when she visited Buffy’s house in Checkpoint.

In Blood Ties, Dawn has a couple of flashbacks to being confronted by the crazy guys in Real Me and Listening to Fear. She also remembers Sobek the snake from Shadow.