DC's lineup consists of super-powered beings large and small. Some of their powers are cosmically outrageous and universe-threatening while others are just menacing enough to get away with petty crime. Metahumans, however, are just one subtype of the many denizens of the comics. While some definitions clash with each other, a true metahuman is a human being from earth who was either born with abilities or was altered by a force that permanently gifted them with inhuman abilities.
Metahumans occur in a number of ways. Some of them are scientists or victims of mad scientists who are the result of a genetic experiment. Others tap into a source of power greater than themselves, such as the Green or the Speedforce. Many of the rest are born with the genetic marker for meta abilities. Whatever abilities they obtain, some are far more dangerous than others.
10 Killer Croc
Waylon Jones was born with a rare medical condition that causes his skin to harden like the scales of a crocodile. After several stints in juvenile detention and prison time for murder, Jones made a new life for himself as an alligator wrestler. He broke their backs with his bare hands, leading to his new name, Killer Croc.
With armored skin, abnormal strength, and a mean streak, he quickly becomes a regular threat to Batman. As time passes, his condition triggers a genetic regression, causing him to both physically and mentally be more like an early, reptilian evolution of humans. Not only does this grant him superhuman speed and agility, but also rapid healing as well. Despite the danger he poses, he's known to do good things.
9 Livewire
First appearing in Superman: The Animated Series, Livewire (Leslie Willis) is a disgruntled shock jock with a disdain for the Man of Steel. She was born with the innate ability to control electricity, but her powers didn't come to full fruition until she stood at the top of a radio tower and was struck by lightning.
In most iterations, she's a sworn enemy of heroes hellbent on putting them in their place. If electricity itself wasn't bad enough, she can also use it to transform matter into almost anything she requires. Additionally, Livewire absorbs energy, making her more powerful. She also exudes energy, causing an electromagnetic pulse.
8 Killer Frost
With the success of the live-action series The Flash, Caitlin Snow, aka Killer Frost, is more well-known than ever. She is a powerful metahuman with ice powers known for her violent behavior. Newer iterations of the character show her as having a change of heart. Now known simply as Frost, she's a proud member of the Justice League of America.
Even still, her powers make her a serious threat in the DC Universe, albeit to villains. Her body is made up of ice-like cells, making her more of an elemental than human. Unlike other metas such as Poison Ivy, Frost doesn't need ice nearby. She generates ice from naturally-occurring water within the atmosphere, creating an endless supply of ammo and weaponry.
7 Everyman
While there are several shape-shifters in the DC Universe, few are as capable as Hannibal Bates, otherwise known as Everyman. By ingesting a genetic sample, he shapeshifts into almost any living creature, human or otherwise. When he shapeshifts, he takes on the individual's full genetic makeup. It's so convincing, he fooled a Green Lantern ring.
This is what differentiates him from individuals such as Beast Boy in that he fully becomes the entity he mimics. His whole genetic structure changes, making him nearly invisible, blending into any society, crowd, or animal pack. He becomes anyone and does anything he wants while in their form.
6 Parasite
Joshua Michael Allen, the current Parasite, earned his abilities through an alien flu virus. It turns him into a large, violet, hulk-like creature that absorbs energy from other super-powered beings. When he does so, he also gains their abilities. This becomes extremely dangerous when he manages to make physical contact with heroes like Superman.
By simply touching the Man of Steel, he instantly becomes the biggest threat on the planet. He also combines abilities if he touches more than one person. In a matter of moments, Parasite evolves from a petty, local problem to an international emergency for the Justice League.
5 Firestorm
A fan favorite metahuman that has appeared in many stories and even on television is none other than Firestorm. He's a complex character considering the Firestorm Matrix combines two identities together. Currently, Firestorm combines the body of Ronnie Raymond with the mind of Professor Martin Stein.
Even though he's considered a hero, Firestorms abilities are both vast and volatile. He has complete control of all the molecules around him, turning a building into water if he wishes. However, Firestorm's existence is the cause of a nuclear reaction. The entity is a living nuclear bomb that must be kept in check. Both individuals that make up the Matrix must coexist well together and fully understand what it means to be Firestorm for their safety.
4 Blockbuster
As a chemist desperately wanting to change his body, Mark Desmond created a serum that gave him both height and strength. Unfortunately, it came with the major side effect of absolute rage, similar to that of Marvel's Hulk. While he's rather mindless, other villains use him to their advantage.
When supervillains need something done as fast as possible with little regard to the chaos it might cause, they call on Blockbuster. He rampages through buildings, maiming and even killing those unlucky few that get in his way.
3 Dr. Light
Dr. Arthur Light of New Earth may not be a prominent villain, but his abilities remain a bit overpowered. Other than being a super-genius, his primary ability is photokinesis, the control and manipulation of light. The full scope of his abilities are still unclear, but he also casts explosive illusions, creates energy constructs, flies through the air, and creates energy blasts.
For a villain with minor appearances, he has the ability to trick people through illusions and create an army of light beings. He's an incredible threat to the people of earth, even if he has yet to use his abilities to their full potential.
2 Poison Ivy
Around since the '60s, Dr. Pamela Isely, otherwise known as Poison Ivy, is a staple of Batman's rogue gallery. Most of her origins pin her as a scientist who, through various genetic experiments, made herself part plant. Her connection to plants also introduces her to an even greater power known as the Green.
Poison Ivy has always been a recurring character in the comics. As such, readers have seen the full extent of her power, time and time again. She brings down buildings and even tortures other supervillains, making her one of the most dangerous metahumans in DC.
1 Reverse Flash
The Flash's arch-nemesis, The Reverse Flash, hates the hero with every fiber of his being. Eobard Thawne, as he's known in the future, is a psychotic speedster determined to make Barry Allen's life a living hell. He's even willing to alter the timeline to do it.
What makes Reverse Flash the most dangerous is that he literally changes existence itself to just to hit Barry where it hurts most. He's even known to erase a person's entire existence but literally deleting them from the timeline. Along with having every other ability a typical speedster has, Thawne even created his own negative Speed Force.