After eight seasons of faux psychic hijinks and goofball hilarity, USA Network’s ‘dramedy’ Psych aired its 121st and final episode “The Break-Up” this past Wednesday, bringing to an end the televised adventures of crime consultant/quasi-Sherlockian observational detective Shawn Spencer (played by James Roday) and his often reluctant partner Burton “Gus” Guster (played by Dule Hill). As a show that was known for its abundance of pop culture references and homages (a prime example being season five’s 12th episode “Dual Spires”, which reunited seven cast members from David Lynch’s early 90s seminal cult classic TV show Twin Peaks), Psych managed to deliver the goods once again with three guest cameos (Deon Richmond, Billy Zane, and Val Kilmer) that were also self-referential running gags throughout the show’s run.

First up is Deon Richmond as Gus’ boss. Richmond played Rudy Huxtable’s friend Kenny (whom she nicknamed “Bud”) in The Cosby Show, whom many people throughout Psych‘s run have asked Gus if he was the actor who portrayed the character. The ironic part of this running gag is that actor Dule Hill, who plays the often questioned Gus, did play a character, Marcus, in one episode of The Cosby Show late 90s spin-off, the simply titled Cosby.

The last two guest stars are both actors whom Psych has referenced by name many times. Billy Zane, who recently appeared in a rather mysterious and very fake commercial for a real life Back To The Future II hoverboard, steps into the shoes of the show’s last bad guy, although the crime-solving story arc of the final episode sort of takes a backseat to the ‘goodbye’ aspect. Zane, who is slightly unrecognizable with a handlebar mustache and balding look (as opposed to his usual clean-shaven and flat-out bald look), plays his businessman villain as suave as Roday’s Spencer always said he found the actor.

Throughout Psych there has been a often mentioned and often referred to yet never seen Officer Dobson. In the last minutes of the show, when we get a glimpse at various characters reacting to Shawn’s ‘goodbye DVD’, we finally get to meet the elusive Dobson, portrayed by none other than Val Kilmer. Kilmer, who has spent recent years making interesting career choices such performing a one-man Mark Twain show entitled Citizen Twain as well as occasionally considering running for Governor of New Mexico, has been the subject of much fondness from Spencer. That Val Kilmer would be the one to play Dobson seems a perfect representative of the pop culture obsession that permeated Psych.

James Roday told EW the story behind the casting of Val Kilmer, and it started with Dule Hill and a friend who runs the LA Shakespeare Festival:

“They do these giant celebrity-laden readings every year, and he said, ‘You know, Val’s done those for us in the past. Val’s actually a really good friend of mine. I wonder if he has any idea how many times you guys talk about him on your show.’ They were like having brunch, and he said, ‘Let’s just call him and ask him.’ And the next thing Dulé knew, he was on the phone with Val, who of course had never seen our show and had no idea what anybody was talking about. But Dulé, being the proactive guy that he is, just put him right on the spot right there on the phone. What’s Val gonna say? ‘Yeah, of course, it sounds fun.’ But then we actually had to put in the legwork,” Roday says. “Val’s got a one-man show that he’s been touring around the country called Citizen Twain. He dresses up like Mark Twain. It’s a passion project of his. I would recommend seeing it if you can. I managed to get to that show and get myself backstage through the help of others, and then I just kind of laid it on. I seized my moment. And then we just chased him through assistants and through his agent to the point where I think it was just easier for him to do it so that he could be done with us. But he was such a peach to work with. I think because there was a little bit of time between when we first made contact and when he came in to do it, he was able to educate himself a little bit about the show and kinda realized, ‘Oh wow, there really is a cult following here, and they really did talk about me a lot on this show, and I get it.’ So I think he got a kick out of that.”

The Psych series finale was followed by the Psych After Show, an hour long interactive Q & A with series creator Steve Frank and the cast, including leads Roday and Hill.