Mario and Luigi have been kicking tail and making games since 1985. The two platforming-plumbers have saved many a castle over their 33-year career. From bashing blocks to trouncing on turtles, the bros have been a household name since the genesis of Nintendo. But what good is a daring adventure to save the princess without a few beasts and bad guys to bounce on the way to recapture the kingdom? Without a monster or two, there's not much room for treacherous peril for our heroes to face, is there? Sure the Mushroom Kingdom is home to the Toads, the Yoshis, and of course the royal house of Toadstool, but what about those monsters and minions under the banner of a certain fire-breathing reptile?

Of course, we're talking about Bowser and his baddies who try to conquer the kingdom at least once a week; those fun-loving fiends who do the best to give us their worst. What would the Mario games be like without the Koopas, Troopas, and the rest of the minions? Too easy, that's what! The Mario Bros have gone up against a menagerie of monsters to save the Princess, and we're going to take a look at some of Bowser's best. What sort of baddie makes our list of the Mushroom Kingdom's most famous maniacs? What makes them iconic to the Super Mario Bros. series? What ways do they keep the two plumbers from their precious princess? Hold on to your hats, paisanos, because here-a-we-go!

27 GOOMBAS

goomba

What better way to start out our list of enemies than with the first enemy Mario encounters on his mission to save the princess? These mushroom-looking monsters have been trudging around the kingdom since the days of World 1-1. The grouchy little fungi come in all shapes and varieties, some growing incredibly massive, others even donning Mario's Tanooki Tail.

At the end of the day, these little guys are not the biggest threat to the kingdom's safety. Like so many creatures on this list, Goombas can be stopped with a simple bop on the head. Don't worry, there are legions more of them scattered throughout the worlds. In fact, they are perhaps the most common enemy, found in nearly all games under Mario's title. The only ones that could compete with them take the place of our next entry.

26 KOOPA TROOPAS

Koopa Troopa

These rascally reptiles parade through various levels and various titles, coming in all shapes, sizes, and shell-colors. The Koopa Troopas are Bowser's main line of defense, showing up in nearly as many levels and worlds as their previously mentioned friends. The troops can march back and forth, climb up fenced walls, and some even fly with capes or wings. They are more versatile than the Goombas, but just about as much of a threat.

The Koopas have also been famous for their appearance in the Mario Kart series. The red, green, and the infamous blue shell have all been popular weapons for many a great Grand Prix. Turns out, their shells are just as deadly on the racetrack as they are on the platforms. Talk about getting shell-shocked.

25 DRY BONES

Dry Bones

The head bone's connected to the shell bone... at least it is for these creepy freaks. Dry Bones are essentially zombified Koopa Troopas. They trudge the same walk cycle and they have the same goal of stopping Mario from finishing the level. The only difference is, these guys are a little harder to put down.

Players familiar with the series will know that no matter how many times they stomp on these skeletal slinkers, they always reform right back. Much like a real zombie, the best way to waste them is to sever their head, or in this case, push it off a platform. Other than that, any power-up or turtle shell should put them out.

24 SHY GUYS

Shy Guy

Making their debut in Super Mario 2, the masked minions of Croak have since become a regular player in the more modern Mario titles. With their strange design, white masks and hoods of various colors, these guys seem like they'd be more at home in a Final Fantasy title than the Mushroom Kingdom. Nevertheless, they've become a practical fixture of the series. Shy Guys, like the Goombas, are the first enemy the player meets in their respective game. They're not much of a threat, though, and can be easily taken out with a radish to the head.

The Character of Shy Guy himself has made several appearances in various other Mario titles, such as the popular Mario Kart series, Yoshi's Island, and even taking an NPC role in the Mario Party games. He's even a popular character among fans and cosplayers. Turns out, he's not such a shy guy after all.

23 NINJIS

Ninji

Coming in with an acrobatic leap, the Ninjis take our next spot. The hopping, feline-like creatures first appeared along with the Shy Guys in Super Mario 2, and have still made their home in the Mushroom Kingdom. Not as docile as the aforementioned Shy Guys, the Ninji will leap or charge at the player if they come within their territory.

This is one of the first enemies in the game that starts to show some intelligence, moving about and trying to stun the player instead of marching forth in a straight line. They have a slight increase in skill, but nothing Super Mario 3 worthy. If nothing else, they're still remembered for their cute design, and that's good enough for us.

22 CHEEP CHEEPS

Cheep Cheep

Ah, the water-levels. How many players have been swept away by the currents, pinned beneath platforms, or fallen prey to these guys? The Cheep Cheeps are honestly a "cheap-cheap" enemy in the Mario games. They don't do much but swim forward, but the controls and environmental hazards of the water-levels never fail to push Mario into their wake.

The fishy fiends have found their way into other titles and even transitioned beautifully well into 3-D. They've also developed a bit more backbone in Super Mario: 3D Land, popping out of waterfalls and fountains. Though still a low-level enemy, it does take a certain amount of skill to bounce on these guys.

21 BLOOPERS

Blooper mario

In the water levels, you have your Cheep Cheeps, and then there are these things. Bloopers are the squid-like creatures that bob and float through the water. Hard to believe such a pesky thing has such a cute name. What makes these enemies different is their clingy nature. Given the chance, they will lunge towards Mario and try to nab him in their tentacled grasp.

A great portion of the water-level annoyance is certainly the fault of these guys. At times, the player will be too busy swimming away from them to notice the oncoming Cheep Cheep or falling platform. Infuriating, yes, and it just keeps going from here.

20 PIRANHA PLANT

Piranha Plant

Yet another common feature of the Mushroom Kingdom's landscape, Piranha Plants have certainly taken a bite out of Mario more than a few times. Whether they're the chomping or the fire-spitting variety, these botanical beasts will certainly pose a problem getting from A to B. With their polka-dot pods and gnashing teeth, they've become quite the aesthetic for Mario games, appearing on many pieces of box art and other materials.

As troublesome as they may be, they are fun to bounce on with a stolen Goomba Shoe. One or two on their own are no sweat and easily extinguished with a well-aimed fireball, but get a field of them together and you've got a situation only a Starman can fix. Some of them even grow to monstrous size and can be a terror to deal with. Horrible and hungry, Piranha Plants are chomping at the bit for a taste of us.

19 BOB-OMS

Bob-omb

Similar to the Koopa's shell, a lit Bob-omb can be a deadly force. A swift kick to the backside will light the fuse and give Mario a chance to hurl them at oncoming enemies. Quick thinking can lead to a much-needed save. Let's just say the results are quite fiery.

These guys might be cute and toy-like, but be careful when playing with them, you will certainly get burned. Their explosive personalities have made them quite popular in the series, making appearances in a few party games and joining the Koopa Shells in the Mario Kart weapon line-up. Whether you need them for a quick escape or a chance to take first place, careful where you lob these dynamite dudes.

18 BOOS

Boo

The Boos take our next spot, don't be surprised if they're a bit bashful about it. Pretty shy for spooky specters, Boos can often be found haunting castle hallways and hanging around the Boo Houses. There are a handful of enemies that will actually give chase to Mario, but none quite so quirky as these flighty fantoms.

Apparating first in Super Mario 3, the Boos have been quite busy since their days in the castles. They've had their own levels, become Mario Kart power-ups, and even got the chance to be the primary antagonists in Luigi's Mansion. Though these guys may not want to show their faces, we'll gladly give them a comfy place on our list.

17 PHANTOS

phanto

Where Boos will float and hide once Mario turns around, Phantos will hunt him down like a horror movie slasher. At first, these things look like pieces of decor, until Mario goes for the magic key. One touch of the key and a Phanto will come sailing over the screen to stop him.

Just when you think you've escaped by making it to another screen, if you are still carrying the key, the thing will come zooming from the corner of the screen like a missile to try to get it back. There are not very many tense moments in Super Mario 2, but this is certainly a contender. It's pretty intimidating for something that looks like what the Phantom wears to Comic-Con. (Art by MDTartist83)

16 BOSS BASS

Boss Bass mario

Just when you thought it was safe to go back in the water, Boss Bass, the big bad fish, comes up with a bad attitude and a hunger for plumber. This plus-sized Cheep Cheep is one tough customer, having the ability to leap out of the water and swallow up Mario whole.

Much like the Cheep Cheeps and Bloopers, the purpose of this fat fish is misdirection. In his levels, you have to be mindful of the rising and falling water, the platforms, and the oncoming enemies, not including the aforementioned fish. We can assure you, these levels are no day at the beach.

15 THWOMP

Super Smash Bros for Wii U Boswer glaring at block

Like the Boos, Thwomps are another fixture of Bowser's castles who seem to just have it in for Mario. Thwomps are the big, grimacing pieces of falling architecture whose mission in life is to simply thwomp Mario down a peg. You know Bowser is going all out on his security system when pieces of the castle want to end the game.

Thwomps are a common obstacle in many a Mario title. They've been a problem in both 2-D and 3-D platformers, minigames, and even shaking up the track on Rainbow Road. Hard-headed and heavy hitters, these sinister stones will surely give you a bumpy ride.

14 BOOMERANG BROS

One of the few Koopas to actually use a weapon against Mario, the Boomerang Bros come correct with a little thunder from down-under. Hurling their titular boomerangs, they will try to cease Mario and his carefree platforming. They're relatively easy to beat, as their projectile goes in a straight line, but don't let fool you. They're as hazardous as the rest of their brethren.

The Boomerang Bros can be found all over the Mushroom Kingdom, and have even lent their boomerangs as powerups in various titles. The blue-clad baddies are a bit stronger than your average turtle, but can still pack a wallop if given the chance. That being said, any seasoned Mario fan will tell you, our next pick is a step above their blue counterpart.

13 HAMMER BROS

Hammer Brothers

These guys give a new meaning to the term "hammer-time." The Hammer Bros will hop up and down, lobbing their sledgehammers in impossible arcs toward the player. They can be found causing hardware-store havoc all throughout the kingdom, even getting their own levels in Super Mario 3.

Timing is everything when going up against these two. One false jump, and you'll be met with a hammer to the head for sure. The best strategy is to simply jump over these guys, or attack them from beneath. This last option should only be performed if there are bricks underneath to break, of course. The Hammer Bros are certainly one of the most difficult species of Koopa you're sure to meet. Approach with caution, and make every jump count.

12 BULLET BILL

Bullet Bill

An icon of any classic Mario title, the ever angry-eyed Bullet Bill comes blasting into our next spot. These pieces of anthropomorphic ammunition have been forcing our favorite plumber to dip, dive, duck, and dodge for nearly three decades. Alone, not so much a threat and they can even be used as platforms, but get into a tight place and they can be quite the hassle.

Whenever these guys aren't popping out of cannons or making airship levels a nightmare, they can be found in some of the landscape of the spin-off titles or as powerups in other games. The most notable instance of Bill outside his normal projectile routine is his appearance as a famous powerup in the more recent Mario Kart titles. The Bullet Bill powerup is basically the Hail Mary of the race track, giving the player a much-needed boost to get out of last place. No matter what side they're on, they're sure to be quite the hotshot.

11 MOUSER

Mouser Fight

"Here, have some bombs!" This radical rodent was a blast to battle in Super Mario 2 but sadly seems to have fallen out of style. His bomb-lobbing boss-fight forced the player to be quick on their feet to finish him off. Since then, however, Mouser has not been featured in any other Mario title.

While it's true Mouser hasn't made an official in-game appearance since 1988, he did have a supporting role in The Super Mario Bros Super Show as Bowser's wisecracking number-two guy. With his shades, bombs, and tough-guy routine, he certainly added to the humorous side of the villains. Will we see this guy again? Who knows, but he's certainly worthy of a mention.

10 CHARGIN' CHUCK

Chuck mario

Always charging from the checkpoint, this football-fanatic is a 16-bit star. Known to most Mario players as "that football guy," Chuck has been ready to run us down since his first days in Super Mario World. Though quite recognizable in his helmet, pads, and cleats, Chuck seems to be forgotten on certain people's lists.

In the early days of development, there was a concept to have many types of Chuck. The idea was to have different variations based on different sports such as football, baseball, and some rumors even suggested hockey. Until his appearance in Super Mario 3D World, Chuck had been missing from the series for an entire decade. Strange he hasn't found a home in Mario's sports games, isn't it?

9 DONKEY KONG

donkey kong

He's the leader of the bunch, you know him well, and he's on our list for kicking tail. We simply cannot have a list like this without including the OG of Mario adversaries, Donkey Kong. The titular nemesis of Mario's first outing in the days of the arcade cabinets, the big ape has become almost as recognizable as the acrobatic plumber.

Though once a barrel-throwing baddie, it seems he and Mario have patched things up and have now become just friendly rivals. Modern gamers have frequently seen DK behind the wheels of a go-cart, besting the Mushroom Kingdom crew at various sporting titles, and even slamming other characters down in the Super Smash Bros series. Whether up against Mario in some of his games or swinging through the jungle in his own platformers, it's always great to see this big ape.

8 WARIO

wario

Though he's more of a greedy trickster than a full-out villain, our favorite fat, yellow, Mario clone Wario was first introduced as the main antagonist of Super Mario Land 2. Since then, he's made mountains of mischief on his quest for riches, simply trying to outdo his famous doppelganger. With a more aggressive style, and a less than chivalrous motivation, Wario has become one of our favorite gaming anti-heroes.

Easily one of the most ridiculous and silly boss-fights in a Mario title, Wario has certainly come a long way from just a fat, butt-bouncing, bad guy. He's since stepped out of the antagonist role and moved to his own platform and spin-off games. Those familiar with the Wario titles are aware of his more assertive attack patterns, choosing to punch, kick, and slam his enemies to the ground instead of hopping on their heads; as well as his appetite for treasure and not the hand of a princess. Relish him or be repulsed, Wario is one of those baddies we just can't completely despise.