In the lead up to 2018’s superhero epic Avengers: Infinity War, Marvel touted the blockbuster as “the most ambitious crossover in history” and — in a sense — they were right. The film marked the beginning of the end for the first era of Marvel Cinematic Universe. It pulled together characters quite literally from all over the Marvel universe in a massive story that would only expand in scope with the following year’s Avengers: Endgame. Despite being a groundbreaking achievement for Marvel, calling it a true crossover is a little disingenuous. All these characters are owned by Marvel and several of the preceding films acted as sequels and follow ups, resulting in the two recent Avengers films being more like a season finale to a lengthy TV show. If one looks back however, one can find potentially even more ambitious crossovers in a seemingly unlikely place, the monster movie genre, and see how it’s a long lasting tradition that continues to this day.

Perhaps the first true “cinematic universe” can be found as early as the 1920s with the advent of the classic Universal horror movies. Phantom of the Opera was the first of these films debuting in 1925 and the 30s and 40s would see the release of Dracula, Frankenstein, The Wolf Man, and many others. These were typically adapted from literature and functioned as standalone films all under the Universal brand but otherwise not interconnected. That would change with 1943’s Frankenstein Meets the Wolf Man in which the titular Wolf Man (Lon Chaney Jr) goes on a quest to find a way to die and end his werewolf curse. His journey leads him to the Frankenstein estate where he does battle with doctor’s monster (Bela Lugosi) before both seemingly perish as the castle collapses and floods. The film plays fast and loose with continuity, pulling some elements from The Wolf Man and the previous Frankenstein films while also making blatant contradictions. Continuity wasn’t exactly at the forefront of the studio executive’s minds and while the film didn’t receive very positive reviews, it’s a cult classic for fans of the genre. Universal would release more monster mashups like House of Frankenstein (1944) and House of Dracula (1945), both of which threw continuity out the window to have the Frankenstein monster, the Wolf Man, and Dracula all meet up. To cap off the 1940s, Universal would release the humorous Abbott and Costello Meet Frankenstein (1948) in which the comedic duo would come into contact with the three previously monsters, ending in a battle that kills off all three. Despite its comedic nature, the film is well regarded by fans and is notably the only time Bela Lugosi would reprise his role as Count Dracula. To call these loosely connected films a cinematic universe would be overselling it as continuity was not a driving force. It was clear that Universal wanted to play around with its characters but didn’t plan for it to be anything more than light entertainment.

Of course, the Universal monsters were all owned by one studio. A crossover to be sure, and very novel for its time, but not a huge legal feat. In the 1960s however, the world would see a union of two of the biggest monster all-stars with 1962’s King Kong vs. Godzilla. The film started as a plan to bring Kong and the Frankenstein monster of all things into battle with one another but plans never materialized. As producer John Beck looked for a production studio, he came into contact with Toho, the studio behind the Godzilla series. As negotiations evolved, the script was revised to pit Godzilla against Kong in Frankenstein’s place. The end result focuses on a pharmaceutical company desperate for publicity taking the giant ape from his home island to Japan at the same time that Godzilla emerges from hibernation and wreaks havoc across the country. The Japanese military seeks to kills two birds with one stone and brings the monsters together so they can kill each other and the film ends with Kong swimming off to sea and Godzilla disappearing without a trace.

King Kong vs. Godzilla was a landmark title for both characters. It would be the first time both monsters would appear in color and was what really kicked the Godzilla series into a full blown franchise with almost yearly releases. To this day the film remains the most attended Godzilla film in Japanese theaters. Godzilla would go on to have more crossovers with other Toho creations like Mothra and Rodan and the studio would get one more film out of Kong, pitting him against his robotic doppelganger, Mechani-Kong, in King Kong Escapes (1967). Toho would even get their own take on Mary Shelley’s famous creature with Frankenstein Conquers the World (1965), featuring a new monster named Baragon who would go on to cross over with Godzilla. King Kong vs. Godzilla remains notable for bringing two pop culture titans owned by two different studios in two different countries together. It manages to be an entertaining crossover that doesn’t just feel like a marketing gimmick. Despite its success, this collaboration would not see the light of day again for several decades. One final bit of connection, the English cut of King Kong vs. Godzilla would replace nearly all of the original Japanese music score with stock audio from Universal’s film catalog, including Frankenstein Meets the Wolf Man.

There wouldn’t be another monster mash on this level until the early 2000s when New Line Cinema would pit two of the most famous slasher villains against one another in Freddy vs. Jason. The film had been in development hell for many years with neither New Line nor Paramount reaching an agreement on how to bring the two franchises together. There were little hints like Freddy dragging Jason’s mask underground at the end of 1993’s Jason Goes to Hell but the two wouldn’t clash until 2003. The film amounts to little more than excuse to see the two fight each other and critics seemed to agree with the film receiving poor reviews but some enjoyment coming from horror fans. The film made a profit but ended up marking the end for both franchises until they were rebooted to middling successes. Since these failed reboots the franchises have remained dormant and Freddy vs. Jason remains a novel, if often forgotten entry in the horror canon.

The following year would see a similar crossover with 20th Century Fox’s Alien vs. Predator. This was not a new concept as the creatures had crossed paths in the world of comics and Fox was very eager to breathe life back into the two franchises. Much like Freddy vs. Jason, the film was in development hell for several years and wouldn’t see the light of day until much later, and would open to negative audience reception. Most found the idea of the Xenomorph and the Predator fighting to be novel and fun, but not enough to carry a weak story and characters. It and Freddy vs. Jason succumbed to the same issues that plague most horror sequels; a lack of imagination and unengaging stories. Just a way to make a quick buck with some mindless action. Ultimately, this became the fate for many of these crossover versus movies. The mashups of the 40s and of the 2000s were received the same way, a fun idea that didn’t amount to much. Even still, these types of films manage to have cult followings.

Nowadays, in the age of sprawling cinematic universes, these monsters have been making attempts to re-enter the limelight. Most infamously is perhaps Universal’s proposed “Dark Universe” that was poised to bring together the classic Universal monsters once again. The absolutely abysmal reception of The Mummy (2017) quickly shut down any plans for future installments, with any further monster movies being standalone works. Legendary Pictures has seen success with its MonsterVerse which brings together Godzilla and Kong. Despite King of the Monsters stumbling a bit, the MonsterVerse movies have enjoyed positive reception and box office returns. Godzilla and Kong are set to clash again in 2021 and time will tell how the film pans out. One thing that is certain is that studios are paying more attention to continuity, with the three MonsterVerse entries so far doing well to build up gradually to the anticipated rematch. In a bizarre twist, many horror monsters are finding new life and crossover potential in the world of video games. The Mortal Kombat series of fighting games have introduced several guest characters that include the likes of Freddy Krueger, Jason Voorhees, a Xenomorph, and even The Terminator and Robocop.

It’s easy to see many of these monster crossovers as little more than cheap entertainment to make a quick buck and get some fan service. While that may be true for a number of these films, there’s something truly unique about seeing monsters cross paths that otherwise would never meet outside of fantasy battles with action figures. At the end of the day, it’s fun. Additionally, looking back at Universal in the 40s or Toho in the 60s shows off some of the same ideas that would be put into practice decades later with the big cinematic universes of today.