The Teenage Mutant Ninja Turtles are such a phenomenon that they've been popular with every generation since their inception. Millennials may recall the heroes in a half-shell the most fondly, but every generation to follow also has a soft spot for Leonardo, Donatello, Michelangelo and Raphael. The nostalgia doesn't only run deep for the totally tubular dudes themselves but also for characters like April, Splinter and the many foes they've faced in the last few decades.

Many of the turtles' enemies have brought some serious power to the table, impressing us with their knowledge, know-how and general panache, but there have been just as many duds who left us longing for even a crumb of dastardly viciousness.

RELATED: 10 Things We Know So Far About Pennyworth

Worst: Walker

Walker from TMNT III

The third of the New Line Cinema Teenage Mutant Ninja Turtles films was the most painful of all TMNT media to watch, and not only for the wince-worthy dialogue and bubbly costumes that made the first film's look seem Oscar-worthy. The villain of the film, Walker, absolutely ruined the movie beyond redemption with his weird cowboy look (what British guy looks like a cowboy, especially in feudal Japan?), lack of any special skills or cool weapons and zero powers.

Walker is the literal worst when it comes to villains. He's more annoying than threatening, and if you needed any proof to back that up just look at his demise, which involved him rescuing a pet canary he left behind.

Best: Krang

TMNT villain Krang

As familiar as everyone is with Krang, they also know that he's a pretty helpless, whiny little guy who demands that The Shredder do his dirty work, get him a body (which doesn't look like a real body at all) and generally cause misery to anyone who has the misfortune to enter his vicinity. The way he whined "Saki" alone could give viewers a headache.

RELATED: Batman vs. Teenage Mutant Ninja Turtles Gets Release Date, Blu-Ray Details

That said, he's been behind some of the boldest plots against the turtles over the years and been one of the few threats against them that actually posed any real danger. Krang was most well-known in the cartoons and comic books, but he also made an appearance in the film TMNT: Out of the Shadows.

Worst: Tokka and Razhar

TMNT villain Tokka and Rahzar

From their "num nums" to their latching onto The Shredder as their mother, the mutated villains of Teenage Mutant Ninja Turtles II: The Secret of the Ooze leave a lot to be desired. While their brute strength still makes them decent roadblocks for the turtles during battle, that doesn't negate the fact that as The Shredder so eloquently put it, "BABIES! THEY'RE BABIES!"

The slapstick comedy that Tokka and Razhar gave in the movie was meant to mirror that of the characters Bebop and Rocksteady in the animated series but it came out as even more annoying, especially since the snapping turtle's CGI was outperformed back in 1984's The Neverending Story by Morla the Ancient One, and the same can be said for the grey wolf regarding the lackluster Twilight werewolves.

Best: Karai

Karai and Shredder from the Teenage Mutant Ninja Turtles cartoon series

A highly skilled assassin, Karai is a complicated member of the Foot Clan whose role is only second to The Shredder himself. Cunning and skillful, she is a force to be reckoned with both in the comic books as well as on the screen. From being The Shredder's daughter to the long-lost child of Master Splinter, the love interest of Leonardo to the mutated serpent, Karai has seen some incredible transformations in her life that have only further made her something to contend with.

Not only is this ruthless warrior strong enough to take on all four brothers at once while fighting, but also important enough to take over for The Shredder in some shows/movies/books.

Worst: Eric Sachs

TMNT villain Eric Sachs

The 2014 Teenage Mutant Ninja Turtle movie suffered from terrible everything, from writing to wardrobe, but its villain was especially awful. Eric Sachs was after the mutagen that transformed the turtles into crime-fighting teens and everything the villain did or said to get it was so cringe-tastic that it's fun to mute the movie and improve his dialogue by inviting children to invent it.

RELATED: Suicide Squad: 10 Things It Actually Did Well

This guy is the worst, but he also basically does nothing save for monologue like an over-hyped villain who never truly posed a threat. We get that you made some ooze and you want it back, dude. Go brew some up and go away. That's the problem with so many villains today: they're too lazy to use their own bootstraps and want to siphon everybody's blood out instead.

Best: Tatsu

TMNT villain Tatsu

While Tatsu, The Shredder's Foot Clan leader in the original Teenage Mutant Ninja Turtles movie, was defeated by both the brothers and Casey Jones and ultimately proved he couldn't take either of them on, he was one of the most threatening villains we've seen them face based not on what he did to them, but what he did to his own people.

Tatsu ruled with an iron fist, using fear and intimidation to beat up the wayward children who came to him in search of a new home if they displeased him or lost a fight. At one point he beats up a kid until we're not sure if he'll make it or not and we wonder how many of the Foot Clan teens he's taken out altogether.

Worst: Dogpound And Fishface

TMNT villain Dogpound and Fishface

It's bad enough to be a literal fish out of water, but it's even worse when your sidekick is also your nemesis. The animated villains in the 2012 cartoon series, Dogpound and Fishface, are pretty much ridiculous. They can't stop nitpicking at one another in order to really accomplish anything and they look too stupid to be fearsome in any way. They're even so terrible in their original mutated forms that The Shredder has to issue them modifications; as a fish, of course Fishface didn't have legs to begin with, which makes him just as helpless as Krang.

The villains don't even have decent names, for Pete's sake. Dogpound even becomes the better-known Rahzar at some point, proving that even his upgrade was a disappointment.

Best: Bebop And Rocksteady

Ninja Turtles Cartoon Bebop Rocksteady

In the same vein that Tokka and Rahzar were designed for comic relief, Bebop and Rocksteady, mutated punks turned into a hybrid rhino and warthog pair, often gave slapstick performances in the Teenage Mutant Ninja Turtles animated series and comic books. The regulars even made it to the film universe, awarding audiences who managed to make it through the previous mutant disappointments. These two delivered, bringing the pain as well as the goofy lines and accented threats to the "toitles."

RELATED: Titans Season 2: 10 Things That Might Happen According To The Comics

No, they don't really have a brain between them, but they manage to make enough mess to stand in the turtles' way--at least for part of an episode--and give us a few laughs in the process.

Worst: General Traag

TMNT villain General Traag

Soldiers made out of rocks. The idea itself is defeated long before General Traag's rock soldiers can even get a foot out of Dimension X, which is the point. Every single time they make an attempt the turtles defeat them. If four teenage reptiles can defeat your entire army, you know you're a waste of a villain.

Most of the time they came off as gruff idiots, and even when they spewed lava they couldn't ever manage to seem imposing on the turtles or the planet itself. Krang should have counted his losses and sought other help the first time his rock army was defeated, but you know what they say about a box of rocks.

Best: The Shredder

The Shredder From Teenage Mutant Ninja Turtles glaring at the viewer

It goes without saying that The Shredder is the best and most fearsome foe that the Teenage Mutant Ninja Turtles have ever faced. Not only does Oroku Saki have the best backstory, filled with complications over the years, but he's also the most highly skilled and motivated villain who actually leads many of the other villains on the list. If all the villains had a showdown, no doubt Shredder would come out on top.

That, of course, accounts for him in his best form. That's not to say there have been plenty of embarrassing incarnations of Shred-Head over the years where he wasn't as formidable of an opponent. At the peak of his powers though, it always takes the combined efforts of the brothers to defeat him.

NEXT: 2 Characters Confirmed And 10 We Want To See In The Matt Reeves Batman Movies