When lights came up in the theater after 2008's Iron Man ended, Marvel fans were already waiting with bated breath for the next stage of the Marvel Cinematic Universe. Nick Fury's cameo in Iron Man's after-credit scene signaled the advent of an interconnected narrative that would soon span dozens of movies and spread outwards into streaming series and television shows. As the story became more complex, characters that were first introduced on the big screen might appear as a guest star on a TV show, and certain movie story elements might be set up by the events depicted on one of the various Marvel series. As the world of the MCU continues to grow ever more complicated, even the most ardent Marvel fans may find themselves forgetting some of the wild things that have happened in the world of the Avengers!

But while all of the wild things that happen might be difficult to keep track of after so many years, these events, characters, and inventions continue to have an effect on the ongoing narratives of the MCU. Whether it's the continued influence of the Roxxon Corporation or the surprise reappearance of General Ross, these forgotten story elements frequently have consequences for our heroes. Fortunately, there's a way of reminding yourself of all the details you may have forgotten without resorting to those boring but comprehensive S.H.I.E.L.D. records. Take a journey back to the earliest days of the MCU as we take a look at 25 of the wild things that Marvel fans always find themselves forgetting about the MCU!

25 LADY SIF: LAST SEEN WITH S.H.I.E.L.D.

First introduced in the original Thor, Lady Sif fought alongside the Lord of Thunder and the Warriors Three (Fandral, Hogun, and Volstagg). In Thor: The Dark World, Sif again appeared to help the eponymous hero emerge from battle victorious.

After the events of the first two Thor movies, Sif made two appearances on Agents of S.H.I.E.L.D., crossing paths with Coulson and his team in the episodes "Yes Men" and "Who You Really Are." However, Sif does not appear in the third Thor movie, Thor: Ragnarok, and the status of this able warrior has yet to be explained on-screen.

24 THE ORIGINAL HUMAN TORCH ALREADY APPEARED

MCU Human Torch

For many Marvel fans, the name of the Human Torch brings to mind Johnny Storm, the flying fire-powered member of the Fantastic 4. But what some fans may not realize is that there was a Human Torch before Johnny, and he's already appeared in the MCU!

In Captain America: The First Avenger, Steve and Bucky visit the Stark Expo in the movie's first act. Included among the displays is the "Synthetic Man," the android also known as the original Human Torch.

23 AGENT CARTER HAD SOME OF CAP'S BLOOD

After the end of Captain America: The First Avenger, Captain Roger's ally and love interest, Peggy Carter, continued to work closely with the Strategic Scientific Reserve, and she had many adventures of her own after the conclusion of World War II.

During the events of season one of Agent Carter, one such adventure led to the discovery of a vial of Rogers's blood. Thanks to the success of the super soldier serum on Rogers, his blood is highly sought-after, and Carter eventually has to toss the vial in the East River to ensure it never falls into the wrong hands.

22 S.H.I.E.L.D. HAD TO CLEAN UP AFTER THE DARK WORLD

Thor the Dark World Convergence

In the third act of Thor: The Dark World, a cosmic event known as the Convergence causes portals to open between realms. In the ensuing chaos, creatures from across the Nine Realms are able to move between worlds.

In the Agents of S.H.I.E.L.D. episode "The Well," Coulson and his team are left to clean up the aftermath of the inter-dimensional adventure. While standalone movies are free to leave the consequences of their adventures unexplored, being part of the MCU means someone actually has to clean up after Thor. Where's Damage Control when you need them?

21 RE-CASTING

Many of the roles in the MCU have been consistent since 2008's Iron Man, but there have been a few instances of characters being re-cast.

James Rhodes, played by Terrance Howard in Iron Man, was replaced by Don Cheadle in Iron Man 2. And while Hugo Weaving portrayed Red Skull in Captain America: The First Avenger, the role was played by Ross Marquand in Avengers: Infinity War. And perhaps most notably, Hulk was re-cast after Edward Norton played him in The Incredible Hulk, with Mark Ruffalo stepping into the purple pants for The Avengers.

20 WAKANDA HAS BEEN MENTIONED

Thanks to an isolationist philosophy and advanced technology, the Kingdom of Wakanda has been able to keep itself largely concealed from the world. Nevertheless, the legendary knowledge and engineering of Wakanda is too good a secret to be kept quiet, and the country was mentioned several times before Black Panther's first appearance in Captain America: Civil War.

In addition to appearing on a computer screen in Iron Man 2, Wakanda is mentioned by Banner in Avengers 2: Age of Ultron. And Wakanda's reputation only continues to grow since King T'Challa went public, being mentioned in the Runaways episode "Big Shot."

19 TONY APPEARED IN THE INCREDIBLE HULK

While The Incredible Hulk premiered in 2008, the same year as Iron Man, it's easy to forget the movie is a part of the MCU, thanks at least in part to the fact that the eponymous lead was recast for The Avengers. As such, Tony's after-credits cameo may seem a bit wild in retrospect!

The scene shows Tony approaching General Ross in a bar to discuss the Avengers Initiative, laying some of the earliest foundations for the larger MCU (and explaining how Tony knew who Ross was when the General appeared in Captain America: Civil War).

18 CAP'S CRUSH IS AGENT CARTER'S NEICE

When Steve meets his neighbor in Captain America: The Winter Soldier, it's immediately evident that he has romantic chemistry with the young woman, but it isn't until Captain America: Civil War that he realizes she is related to his long-estranged love, Peggy Carter.

But while Sharon Carter may be the niece of Steve's former love interest (whose funeral they are attending when Steve is struck by the realization), Captain America and Agent 13 still share a kiss before the credits roll.

17 MOCKINGBIRD HAS ALREADY BEEN INTRODUCED

Bobbi Morse, also known as Mockingbird and Agent 19, has a long history in Marvel comics. In addition to being an accomplished agent of espionage for S.H.I.E.L.D. and serving as a member of the West Coast Avengers, Mockingbird has a romantic past with Clint Barton.

What Marvel fans might not realize is that this legendary hero has already appeared on-screen in the MCU! After being introduced in the Agents of S.H.I.E.L.D. episode "Laws of Nature," Mockingbird appeared on the series for several seasons before leaving the team to embark on her own adventures. Her current whereabouts are unknown...

16 INHUMANS ARE ACTIVE ACROSS THE PLANET

The Kree have appeared in the Guardians of the Galaxy movies, but their creation, the Inhumans, have yet to make an official big screen appearance. Nevertheless, Inhumans are active across the planet, as shown in Agents of S.H.I.E.L.D. and Inhumans.

Inhumans, the ancestors of ancient humans who were subjected to Kree experimentation, develop fantastic powers and characteristics after undergoing the process of teregenesis. At the end of the Agents of S.H.I.E.L.D. episode "S.O.S.," Terrigen crystals fall into the ocean, causing teregenesis to occur in individuals around the world.

15 FLYING CARS HAVE BEEN AROUND FOR DECADES

In the first act of Captain America: The First Avenger, Howard Stark takes to the stage during his technology exhibition to announce that cars capable of flying through the air are only a few years away! A breathless audience watches as the demonstration of a flying car ends with an unceremonious return to to the stage.

But Howard's promise of a flying car holds true, and one that manages to stay in the air appears a few years later, during the first season of Agent Carter.

14 BATTLE OF NEW YORK SET-UP THE NETFLIX SHOWS

When Loki led a chitauri invasion of New York City in The Avengers, there were lasting consequences for the MCU. In addition to leaving behind the technology utilized by the Tinkerer to power the Vulture in Spider-Man: Homecoming, the attack also created the conditions that set-up the plot for Daredevil, the first Marvel Netflix show.

According to dialogue from the first season of Daredevil, Wilson Fisk consolidates his power thanks in part to the increased criminal activity that occurred in the devastation left behind by the Battle of New York.

13 TONY DIDN'T LIKE BEING HANDED THINGS

In Iron Man and Iron Man 2, it is noted on several occasions that Tony possesses an unusual tic: he does not like being handed things directly, instead preferring they be passed through an intermediary, such as his bodyguard, Happy Hogan.

The tic, which recalls the eccentricities of legendary real-life inventors like Howard Hughes, is alluded to in the opening scenes of The Avengers. But as the stakes of the MCU have risen there has been less time for Tony's eccentric behaviors, and this character trait has been largely forgotten.

With one presiding on Saakar and the other making his home on Knowhere, it may seem wild to some Marvel fans that these two Elders are related to one another! Although the exact nature of their familial relationship is difficult to describe in human terms, they might fairly be considered to be brothers.

A painting that appears in the Collector's fortress, the setting of the Guardians of the Galaxy: Mission Breakout attraction at Disney California Adventure, depicts the pair having a heated debate during a board game. When it comes to brothers, some things remain universal!

11 SENATOR STERN WAS HYDRA

In Iron Man 2, Tony is brought before a Senate committee headed by Senator Stern, who demands that the Iron Man armor be surrendered to the United States Government. The committee relies on questionable expert advice from Justin Hammer of Hammer Industries to demonstrate that acquiring the armor is a matter of national security.

But in Captain America: The Winter Solider, Senator Stern is revealed to be secretly working for HYDRA, suggesting sinister ulterior motives for his demand that Tony surrender the Iron Man armor.

10 ROXXON HAS FINGERS EVERYWHERE

The Roxxon Corporation is one of the biggest companies operating in the world of the MCU, and it has fingers everywhere.

First appearing on the big screen in the Iron Man movies and the DVD one-shot A Funny Thing Happened on the Way to Thor's Hammer, Roxxon has also made appearances throughout the various MCU shows, with references being made to the corporation in RunawaysIron Fist, and Agents of S.H.I.E.L.D. In addition, the corporation has played key roles in the plot of stories featured on Agent CarterDaredevil, and Cloak & Dagger.

9 ELON MUSK HAD A CAMEO

RDJ as Tony Stark

While MCU fans are used to keeping their eyes peeled for a Stan Lee cameo, they may have forgotten one of the wildest cameos in the entirety of the franchise: Elon Musk's line in Iron Man 2!

Tony crosses paths with the eager inventor when he arrives in Monaco for the Grand Prix, and while Musk is eager to share a new idea with Tony, Tony is somewhat preoccupied with other priorities. Nevertheless, Musk allowed the Iron Man 2 scenes set at Hammer Industries to be filmed at SpaceX facilities.

8 JARVIS AI WAS BASED ON AGENT CARTER'S SIDEKICK

Agent Carter Peggy Carter and Jarvis

Beginning in Iron Man and until partway through the events of Avengers: Age of Ultron, Tony's Iron Man suit operates thanks to the assistance of J.A.R.V.I.S., an AI with a British accent and a polite demeanor.

While the name J.A.R.V.I.S. is an acronym (for "Just A Rather Very Intelligent System"), it also reference's the name of the butler who worked for Tony's father Howard, Edwin Jarvis. Jarvis's on-screen adventures have depicted him as Peggy's stalwart sidekick on both seasons of Agent Carter.

7 CAP CAN'T GET DRUNK

In Captain America: The First Avenger, Steve is devastated when he believes that his best friend Bucky has fallen in battle. Destitute, he turns to a bottle for comfort, only to discover one of the effects of the super soldier serum that transformed him into Captain America is that he's physically incapable of becoming intoxicated.

Agent Carter admits that the inability to get drunk was one of the effects anticipated by Doctor Erskine, due to the serum's effect on Steve's metabolism.

6 WHIPLASH'S FATHER APPEARED IN AGENT CARTER

In Iron Man 2, Tony faced off against Ivan Venko, otherwise known as the supervillain Whiplash, who uses arc reactor technology to create devastating weapons. Ivan claimed that his father had been robbed of what was rightfully his and left destitute as a result of the actions of Tony's father, Howard.

Ivan's father would appear on-screen in the first season of Agent Carter, where Anton meets Peggy when she seeks his assistance in the episode "Now is Not the End."