Accidentally Accurate: Crosses over with Hilarious in Hindsight. In Weapons of Self Destruction, Williams joked that, instead of a German pope like Benedict XVI, there would be a Latin American pope (like "Pope Enrique"). Four years later, Jorge Mario Bergoglio of Argentina would become Pope Francis.
One side-splitting Easter Egg on his Live from Broadway DVD was a rapid-fire montage of all the cuss words he used in the routine.note To find it, scroll all the way down through the menu screen then hit the right arrow button at the last option (or click here); if a Parental Advisory symbol comes up, have fun.
In one routine, he notes that the parents in his audience apparently ignored the "18 and up" label on the performance flyers. "Kids, you're going to learn some new words today!"
Dirty Old Man: Often referenced sex and porn in his stand-up routines. The final stretch of his last televised special, 2009's Weapons of Self Destruction, has him imagining what porno versions of some of his own movies would be like!
Drugs Are Bad: A staple of his later stand-up shows, often drawing from his own experiences (particularly involving cocaine and alcohol). One exception seems to be marijuana: while he brutally mocked stoners in 1986's Live At The Met, in Live On Broadway and Weapons of Self Destruction he was more favorable towards pot (one routine in Broadway is about how pot is less harmful than alcohol). One of his one-liners in particular stands out:
Cocaine is God's way of telling you that you're making too much money.
Gallows Humor: He knew the power of comedy to alleviate sorrow very well, which is why he was always trying to get a laugh from people. A story goes that he went to visit Christopher Reeve after his accident, and came into the hospital room with a lab coat and talking in a thick German accent, later said to be the first time Reeve smiled after the accident. When Robin died, the knowledge that he was fighting demons gave the world a lot more awareness of this trope.
Harpo Does Something Funny: Several of the movies and television shows he was cast in had scripts that said stuff like "Robin can go off here" at numerous intervals. In particular, Aladdin had numerous outtakes of extra footage where the animators let him ramble on unscripted so they could later cull the best bits to animate for the film.
Hidden Depths: Everybody knows of his comedic and dramatic skills, but he also can sing and his first recorded stand up event in San Fran ends in a song, he also sang in Aladdin.
Ivy League: Williams attended Julliard (and roomed with Christopher Reeve), which he pointed out when asked why he started taking on dramatic roles.
I Want My Mommy: In his comedy skit "Shakespeare (A Meltdowner's Nightmare)" from Reality, What A Concept, his character (a night watchman at a nuclear power plant) cries out "WHERE IS MY MOTHER?" when he inadvertently creates a chain reaction by pulling the control rods of the reactor core.
Large Ham: Does this really need justification? We're talking about Robin Freaking Williams here. Perhaps most noticeable when he appeared as the bit character Osric in Kenneth Branagh's HAMlet.
Parody Religion: His comedy album Reality, What A Concept has a segment where he plays the character Reverend Earnest Angry, imitating popular televangelists of the day and promoting the religion of Comedy.
Son:Popeye wasn't good for anyone! Who are you kidding?
Sesame Street Cred: Along with his appearances on the trope-naming show, he did plenty of family-friendly roles and works alongside the more adult ones, particularly in The Nineties.
Throw It In: Known for fighting with directors over how far he can vary from the script. Often it came down to "One good take done straight, then you can have fun."
Tom Hanks Syndrome: Zigzagged — he showed in later years that he could definitely carry serious drama, but comedy was still what he was most famous for, and he still did comedy flicks regularly up until he died. Even his posthumous releases are a mixture of comedy roles and dramas.
Troll: Oh hell yes. From messing around with the cameramen on the set of Johnny Carson's Tonight Show, to buying Conan O'Brien a bicycle, bright green and orange with shamrocks on it, just so Conan would look silly riding it.
True Companions: He and Christopher Reeve had a very close relationship starting from when they were at Julliard together. While there, they promised each other that whoever made it first would take care of the other. When Reeve had his accident and was about to have a risky surgery that could have killed him, Williams burst into his room pretending to be a Russian doctor and made Reeve laugh for the first time since becoming paralyzed, which made Reeve realize that he still had the will to live. Williams was a constant supporter of Reeve, even helping to cover his friend's medical costs, and after both Reeve and Reeve's wife passed away, swore that he would take care of their now-orphaned son.
A "Celebrity Jeopardy" sketch in 2000. Robin is played by Jimmy Fallon, who does a pretty good voice impression. (When Williams died, Fallon, who by then was hosting The Tonight Show, did a tribute to him on the show that aired the night after, including excerpts of Williams' first Tonight Show appearance in The Seventies.)
Robin actually engaged in some self-mockery in a 1986 episode he hosted in a sketch where he played himself as an Shakespearean actor who can't stop going into his improvisational routines, enraging William Shakespeare himself. In another skit, Dana Carvey played his hyperactive son years in the future.
To celebrate the 25th anniversary of Back to the Future, there was a sketch of previously unseen "audition tapes" for the film, in which Jon Hamm played Williams, auditioning for the part of Doc Brown.
In "Buster and Babs Go Hawaiian", in a rather dated reference, Robin asPeter Pan is seen flying around outside Amblin studios. He says "I can fly. Look ma, no wires!" before crashing into something offscreen.
A short in "Henny Youngman Day" had Babs going to a local club's Open Mic Night to try to spark a career in Recorded and Stand-Up Comedy, only to find out that the in-world version of Robin Williams had stopped in for a surprise engagement. Babs choked out on stage until Robin (who had been told he was the final perfomer of the night) comes back out to give her an assist.
In Living Color! featured a 1994 sketch where Jim Carrey played an obnoxious, hyperactive Robin at the Academy Awards. He was seen to make light of the Oscar statuette and the late film producer Irving G. Thalberg and interrupting actors playing James Earl Jones and Whoopi Goldberg (the latter of which grows tried of Robin's annoying antics and beats him about the head with an Oscar). Hilarious in Hindsight, as this skit aired just after Carrey's own career took off.
The episode "Mypods and Boomsticks" featured The Genie in Homer's dream sequence (voiced by Dan but obviously a caricature of Robin's version). This was mainly a Shout-Out to Aladdin: The Return of Jafar, in which Dan Castellaneta took over the role of the Genie when Williams refused to sign on due to contract violations on Disney's part.
In one of the comics, the family has just gotten a new satellite dish and is channel surfing with Bart. They come across a show called Celebrity Alien Autopsies and features, you guessed it, Mork on the autopsy table, wisecracking as usual.
In one episode, a hole in the ozone layer forces everyone in Springfield to stay indoors. Kent Brockman reports that the only people who're safe enough to go outside without risk of being harmed are extremely hairy people, bringing up Williams as an example.
Episode "Bendin' In The Wind'' featured robot Patchcord Adams. Bender wanted to kick his ass.
The movie Bender's Game featured a scene where Mork from Ork is referenced with Orcs as Mork. Then the party kills them while telling them to shut up. It doesn't work.
Frank Caliendo has a very brief Robin Williams impression that he's been known to do. It goes something like "Joke not working, just switch voices." He even did a whole routine where Williams is in a remake of The Wizard of Oz starring him (in all the roles) and directed by Quentin Tarantino.
The first episode of Bob & Doug (the animated series about The McKenzie Brothers) had yet another spoof of John Keating, who does the typical shtick before two police officers show up to take him back to "the home".
Teacher: They can't catch me, not while I have this! (points to shoe, leaps out the window) CARPE DIIIEEEEM!
It featured a teacher who thought he was John Keating, telling the class to "seize the day", "carpe diem" and the like. His class assignments are things like "tell 10 people you love them today". The kicker? He's an accounting teacher.
There's also a point in that same episode where Jeff is wearing a Mork costume.
The Onion poked fun at him occasionally — he vanished on a "free association" bender during the shoot of a movie version of My Three Sons when his improv got out of hand, and in the book Our Dumb Century we learn that scientists warned the U.S. government about "encroaching Robin Williams body hair" in the late 1970s.
When the orcs attack Balin's Tomb in The Fellowship of the Ring, the Rifftrax claims that they're actually something worse-"Morks! Hundreds of Robin Williamses!"-and goes into a brief impression.
Though he doesn't appear on-panel, Dork Tower had him as a member of The League of Extraordinary GentleGamersnote Along with Wil Wheaton, Curt Schilling, and Vin Diesel, pestering game store owners about his tabletop gaming characters.