Buffy and Joyce’s grave stones (seen in The Weight of the World and The Gift) are the same font and design.

The Burrower demon is a parasite that lives in the bodies of human beings. It yearns to make a connection, usually through sexual intercourse, and body-jumps between hosts. When the parasite leaves a host, the body decays at a rapid rate as the human’s life force has been drained. Burrowers …

The ‘Veronica Mars’ fansite marsinvestigations.net has profiles on all of the characters on the show, including Kendall Shifflet Casablancas, who is played by Charisma Carpenter (who played Cordelia Chase). The first paragraph of her profile is:

“A shallow, bitchy cheerleader until she devoted her life to helping the helpless and seducing …

In Soul Purpose, Eve uses a Selminth parasite on Angel. It’s teeth inject an anesthetic, and it pumps neurotoxins into the body causing paralysis, hallucinations and fever dreams.

In Soul Purpose, Harmony confuses Machiavelli with the perfume Prince Matchabelli, “It’s Matchabelli, Einstein, and it doesn’t come in a can.”

In Soul Purpose, Gunn and Wesley call on Spike, who says, “Well, look who’s come to call— Crockett and Tubbs.” Crockett (played by Don Johnson) and Tubbs (played by Philip Michael Thomas) were two detectives in the TV series Miami Vice, which ran for five seasons on NBC from 1984 …

In The Cautionary Tale Of Numero Cinco, Number 5 calls Angel’s heart a “dried-up walnut of a dead thing”. When Fred dissects Angel in his dream in Soul Purpose, she finds his heart and says, “Hey! What do you know? It is a dried-up little walnut.”

A gymnastics expert, Danielle Nicolet (who played Tamika in Harm’s Way) has also appeared in So noTORIous, Crumbs, Second Time Around, CSI, 3rd Rock from the Sun, Undressed, Shadow of Doubt, In the House, Where Truth Lies, Loaded Weapon 1, Family Matters, and Almost There!

Tamika was an employee at Wolfram & Hart, who became jealous of Harmony’s position in the company. She tried to frame Harmony for killing a human by drugging her with Rohypnol and killing her date. Harmony finally realised who had set her up and killed Tamika with a chopstick.

Fred hangs a poster of the Dixie Chicks in her lab in Conviction (we see the poster again in Shells). Fred also tells Harmony in Harm’s Way, “Anyway, if you want to hang out again sometime, we could grab some wine, jam to the Dixie Chicks.” The Dixie Chicks …

Angel discovers in Harm’s Way that his company owns the Los Angeles Police Department, a fact that Detective Kate Lockley appeared to be unaware of.

When Spike drinks from the Cup of Perperual Torment in Destiny, he realises the drink is actually Mountain Dew, a caffeinated, sweet citrus-flavored soft drink produced by PepsiCo, Inc.

The Angel episode Destiny is a sequel to the Buffy episode Lies My Parenmts Told Me, in which we see Spike being sired by Drusilla. In Destiny, we see a flashback to Spike’s first meeting with Angelus. Back in present time, Spike references the events seen in Lies My Parents …

In a flashback to 1880 in Destiny, Angelus says to Drusilla, “Darla and I had a little spat. Her precious master sent for her. You know Darla. Master’s pet.” He’s referring to The Master, who was Darla’s sire.

In Conviction, Harmony gives Angel some blood saying, “Pretty good, right? The extra ingredient is otter.” Later, in the episode Destiny, after becoming corporeal, Spike drinks Angel’s blood saying, “Oh, God. It’s bloody ambrosia. Is this otter?”