Pokemon is an undeniably popular property, and that's thanks in no small part to the collectible creatures at its center. The titular pocket monsters are creatively designed and visually appealing, with each one sporting unique elemental abilities. This makes collecting them all an addictive challenge for players the world over. Don't let this lure oneself into a false sense of security, though.

RELATED: 10 Gen 1 Pokémon With The Most Creative Designs

They may look cute on the outside. However, Pokemon are still presented as wild animals, and wild animals don't always get along with people. In fact, they're prone to lash out when threatened or irritated, possibly injuring or even killing anyone in the vicinity. The Pokemon anime mostly avoids this by showing the friendship between monster and trainer. In a show with hundreds of episodes, though, some adventures are bound to end with humans on the receiving end of some nasty attacks.

10 Pikachu Meets Ash

Ash meets Pikachu in Pokemon

Ash and Pikachu may be one of the most iconic duos in anime, but they didn't exactly start off on the right foot. Ash was all set to start his career as a Pokemon trainer, but by the time he reached Professor Oak's lab, all that was left was an ornery little Pikachu.

The electric rodent shocked Ash every time he came close. Theoretically, this would stop once the two became friends, but it still happens occasionally throughout the show. It's a miracle that Ash isn't a vegetable by now.

9 Charizard Roasts Ash

Charizard burns Ash in Pokemon

Ash's Charmander started friendly enough. Unfortunately, that didn't last. Once it evolved into a Charmeleon, the fire-type lizard frequently disobeyed and even attacked its trainer. This alone would cause bodily harm, but it only got worse after the Pokemon turned into a Charizard.

As one would expect, this flying fighter is far more powerful than its predecessors (and twice as stubborn). It hits Ash with a Flamethrower attack every time it's summoned. For as many times as the kid endures this, he should be dead a hundred times over.

8 Tentacruel Destroys The City

Tentacruel destroys the harbor city in Pokemon

What starts as an animal conservation tale soon turns into a Godzilla knockoff. To make way for a hotel, a developer attempts to rid her local harbor of a group of Tentacool. This backfires when one of them evolves into a Tentacruel and goes on a rampage in the city. Whoops.

This vengeful Pokemon destroys several, multistory buildings, presumably killing hundreds of citizens in its retaliation. No wonder this episode was banned from reruns after 9/11. The imagery may hit a little too close to home for U.S. audiences.

7 Haunter Pulls Ash And Pikachu's Souls Out

Ash and Haunter in Pokemon

Is this what happens to all people when they die in the Pokemon world? Ash and Pikachu are the unfortunate victims of a chandelier, which falls on top of them, and seemingly renders them unconscious. That's until a Haunter comes along. While it appears eager to help, the ghost-type Pokemon actually pulls the two heroes away from their physical selves. It's a scene straight out of The Twilight Zone.

RELATED: Pokémon: The 10 Scariest Ghost Pokémon, Ranked

Everything, from the visuals to Haunter's pantomime explanation, tells viewers that Ash and Pikachu are now ghosts. Whether intentional or not, the creepy Pokemon may have killed them. What a cheery thought.

6 Mewtwo Strikes Back

Mewtwo strikes back in Pokemon

Ever wonder what would happen if Frankenstein's monster was a Pokemon? It all started when Giovanni, the leader of Team Rocket, funded a scientific project to clone Mew, the most powerful Pokemon of ancient times. Unfortunately, the resulting Mewtwo didn't like being a freak of science or a living weapon.

Rebelling against its creators, the psychic Pokemon destroys their facilities, killing dozens of people in the process. The fact that Mewtwo looks more humanoid than many other Pokemon makes the sequence more unsettling.

5 Entei Kidnaps Ash's Mom

Entei abducts Ash's mother for his "daughter" in Pokemon 3

The Pokemon anime has never been afraid to get weird, but the movies and specials take that to a whole new level. In one of the films, a little girl's deceased father is replaced by Entei, one of the legendary dog Pokemon. To grant her wish for a mother as well, the mutt abducts Ash's mother, hypnotizing the woman into filling the role.

Humans capture Pokemon all the time. It's not often that the shoe is on the other foot. It makes you wonder if the legendary ones do this a lot.

4 Iris's Confusing Loss

Chandelure in Pokemon

It turns out chandeliers are jinxed (no pun intended) in the world of Pokemon. The physical pain may be minimal this time around, but the emotional pain is a different story. When the characters compete in the Wishing Bell Festival, they must race to the top of Mistralton Tower. Sadly, a Chandelure (yes, a chandelier-shaped Pokemon) hits Iris with a Confuse Ray toward the end, resulting in her losing the contest. Even worse, she thinks she won.

RELATED: 10 Fire-Type Pokemon That Deserve Another Evolution

She'll eventually realize this isn't the case. The highest high will be followed by the lowest low. For cruelly causing that kind of disappointment in someone, Chandelure should be ashamed.

3 Litwick Sucks (Life)

Litwick takes aim at the characters in Pokemon

Many shows, particularly adventure shows, have a haunted house episode. The characters stumble onto a mansion or castle, stupidly venture inside, and become victims of a slew of scares. This Pokemon episode proceeds in much the same way.

What's disturbing, though, is the sinister stuff beneath the surface. While the heroes have been toiling about, the resident Litwick have been stealing their life force. It's annoying enough when they do it in battle. Had the characters stuck around the mansion, they would have presumably wasted away into nothing. Who knows how many other lives Litwick has claimed?

2 Ultra Ruin Lives Up To Its Name

Ultra Ruin is destroyed in Pokemon

Tentacruel wasn't the only colossal Pokemon to level a city. Ash and Pikachu encounter the eponymous ruins before being chased by a hostile Guzzlord. They're then told that this rogue Pokemon appeared one day and lashed out at the residents of this city. Unable to stop it, the people were forced to flee.

With that, you have the closest Pokemon has ever come to a post-apocalyptic setting, and it's all brought on by one of the pocket monsters themselves, albeit one that's not all that. Even in the face of such destruction, humans still keep these creatures as pets. That should tell you something.

1 Every Time Team Rocket Blasts Off Again

Team Rocket blasts off in Pokemon

These mischievous clowns are as indestructible as the Wet Bandits from Home Alone. They repeatedly try to swipe Ash's Pikachu and other Pokemon, but the heroes defeat them every single time. For whatever reason, the final blow of each battle hits both them and their Pokemon, sending them flying into the sky.

Not only can these guys withstand whatever elemental Pokemon attack comes at them, but they can also survive falling from hundreds of feet after "blasting off." That takes the endurance of a god - or Wile E. Coyote. If anyone was going to bear the most Pokemon-human attacks on the show, it might as well be Team Rocket.

NEXT: 10 Pokemon Games That Deserve Remakes