The trailer for Stranger Things season 3 introduces what looks to be a brand new monster - but could this creature actually be Jake Busey's character, Bruce? The first-look footage was jam-packed with intriguing clues on what's to come in Stranger Things season 3. The Duffer Brothers like to play coy when it comes to revealing story details, but they provided just enough to get fans theorizing.

No matter how long Stranger Things lasts in terms of seasons, the series has accomplished the status as one of the most popular TV shows in recent memory. The stellar cast featured many new faces that are now some of the most sought after actors in the industry. Some have even seen resurgences in their careers due to their roles in the series. It's no question why anyone would jump at the chance to have a role in Stranger Things, which is why season 2 is filled with several new faces; some already established names while some are new.

Related: Stranger Things Theory: Eleven Will See The "Future" In Season 3

Among the new cast members is Cary Elwes (The Princess Bride), who's set to play Mayor Kline, a man more caught up in his own image than doing what's best for the town. He's also the one behind the construction of the Starcourt Mall, a key location for the plot of Stranger Things season 3. Then there's Maya Hawke (Little Women) who plays Robin, a fellow co-worker of Steve at Scoops Ahoy! in the mall. Jake Busey (The Predator) will also make his Stranger Things debut in season 3, but it seems his role could be more significant than first thought.

Stranger Things Season 3 Introduces A New Monster

Stranger Things 3 Trailer - Upside-Down Monster

Each season, the Duffer Brothers take the lore surrounding the Upside-Down to a new level. First, there was the Demogorgon in Stranger Things season 1. Then, viewers were introduced to the Upside-Down's even more menacing big bad, the Mind Flayer and its army of Demodogs in season 2. For Stranger Things season 3, the full-length trailer's final moments gave viewers their first look at Stranger Things' new monster, one that's even more mutated than the rest of them.

During the final 30 seconds of the Stranger Things season 3 trailer, Jonathan comes face to face with a ghastly-looking beast. The creature is unlike anything seen thus far in the series. It has crab-like appendages and a surplus of sharp teeth. The blood-soaked skin hints that this monster could have recently mutated from something - or possibly someone - else. Based on the first look footage, whatever this thing is, it's definitely not a Demogorgon.

Related: Stranger Things Season 3 Trailer Breakdown: 25 Secrets & Reveals

In Stranger Things season 2's ending, it's heavily implied that the Mind Flayer will return. Eleven sealed of the gate to the Upside-Down, trapping the Shadow Monster, but the creature is very much alive. Even though it will have its sights set on Eleven, the one person in Hawkins who could match its power, it seems likely that the creature will be back with a vengeance and ready to take down anyone who gets in its way. With this new creature also in the mix, the lives of those in Hawkins are about to get very difficult again.

An Infection Could Be Spreading In Season 3

Stranger Things 3 Trailer - Billy Infected

At the end of Stranger Things season 2, all of the remaining Demodogs were killed when Eleven closed the gate. Many of them, including Dart, were still in the tunnels that the kids discovered under the pumpkin patch. The labyrinth of tunnels spread underneath the entire town of Hawkins, but the bodies of the dead Demodogs would've been left untouched - that is, until season 3.

Before Netflix dropped the official Stranger Things season 3 trailer, they released a season 3 teaser featuring rats scurrying through a warehouse. Netflix took to social media to hint at the significance of these little rodents proving their significance to the new season. The rats are shown again briefly in the full trailer, and their prominence to season 3 might be connected to the new monster. Rats can even be seen in the lower half of season 3's official poster, which was released as part of the premiere date announcement.

Historically, rats have been known to spread disease. That doesn't mean that the rats could be spreading the bubonic plague across Hawkins, but they could be carriers for something just as dangerous. If the rats ate the corpses of the Demodogs in the underground tunnels, it's very possible they're now carrying something linked to the Upside-Down. If the rats are infected, they could very well transmit that infection through humans. The fact that they're running around above ground puts everyone at risk of catching the contagion.

Page 2 of 2: The New Monster's Identity & What It Means For Stranger Things

Stranger Things Season 3 Trailer - Bruce

Theory: Jake Busey's Bruce Is Stranger Things' New Monster

Actor Jake Busey will make his Stranger Things debut in season 3 as a new character named Bruce. Along with Mayor Kline and Robin, this trio of new characters will undoubtedly play major roles in the upcoming installment. Bruce is described as a cagey reporter for the Hawkins Post. Not much else is known about the character, but he's quickly shown in the trailer walking down a hallway covered in blood. His location in the scene is very telling in connection to the footage of the new monster.

When Jonathan comes face to face with the monster at the end of the trailer, it looks to be the same exact hallway where Bruce is shown. It's possibly a hallway in a hospital based on the lighting and items shown along the walls. The quick montage of scenes reveals that the monster is mutating as it approaches Jonathan at the end of the hallway. It's plausible that Bruce was bitten by one of the rats and got infected, which ultimately turns him into this new monster. Earlier in the trailer, Jonathan and Nancy are shown what is presumed to be the office of the Hawkins Post. If they come in contact with Bruce or get into some disagreement with Bruce's reporting methods, it would make sense why Jonathan would become a target.

Related: Why Stranger Things Season 3's Trailer Uses A Song From 1971

If Bruce is infected, there will surely be others, right? Billy can also be seen in the trailer sporting a gnarly looking wound on his left forearm. While in the shower, he seems distressed about the wound spreading which might be the early signs of the mutation. If he, too, came in contact with one of the infected rats, he could be the next human to transform into a monster. If that is indeed the case, then the Upside-Down will soon have a new horde of monsters ready to wreak havoc on the town of Hawkins. This time around, killing the monsters would mean killing the town's own friends and family. After all, the seventh episode of season 3 is even titled "The Bite," thus indicating that someone becomes the target of a deadly encounter.

What This Means For Stranger Things' Future

Stranger Things 3 Trailer - Battle at Starcourt Mall

Even after battling the Demogorgon, a horde of Demodogs, and the Mind Flayer, Eleven and her crew will never be able to live a normal life without the worry of another threat. Their uneasiness is obviously warranted considering everything that they've been through. This time, however, it won't just be a small segment of the town swept up into the danger. Even though Hopper has done a tremendous job in keeping the threat away from the entire town, it would be impossible to protect everyone from a potential, raging epidemic.

The previous monsters emerged from the Upside Down but an infection spread by animals means that the normal world is now threatened without the presence of the Upside-Down. There doesn't need to be an opening of the gate or a break into the other dimension for the Upside-Down to affect the world. This makes any human a potential target. For a season described as darker and more action-packed, a wider threat would almost be impossible to contain.

The Upside-Down may no longer be a Hawkins problem after season 3; this might become a worldwide threat depending on the outcome. Would it be possible for the Mind Flayer to control those infected by the rats the same way it controlled the Demodogs? During the trailer, a quick shot of two women are shown and they look like they are being mind controlled. They are walking aimlessly with wide-eyes while Fourth of July celebrations can be seen in the background. The July 4th holiday is the perfect place for the contagion to spread as most of the townspeople converge to the fair. "One summer could change everything" is the tagline for Stranger Things season 3, after all, but it looks to be a warning for all that call Hawkins, IN, home.

More: What To Expect From Stranger Things Season 3