I'm Your Worst Nightmare

A common way for a character to announce him/herself in an intimidating manner. It doesn't matter whether he's a good guy or a bad guy, as long as the character is Badass enough to live up to this claim. That is, unless people are spoofing this line (often by the second character describing his actual worst nightmare).

Compare Prepare to Die.

Not to be confused with Your Worst Nightmare (which is about actual nightmares).

Anime and Manga
"Piccolo: I think you'd better let the boy go. Turles: Oh? Is that right? And just who are you? Piccolo: I'm Your Worst Nightmare. Turles: I'm trembling in my boots."
 * The Dragonball Z dub seemed to enjoy characters using this trope. And having its "victims" point out how unintimidating they sounded.
 * Tree of Might Ocean Group Dub

"Burter: Hi! I'm Your Worst Nightmare! Burter! Goku: I'm not afraid of dreams."
 * Goku vs Burter and Jeice

"Goku: Ally to good, nightmare to you!"
 * The final sentence of Goku's I AM speech after he became a Super Sayian to Frieza in the Funimation Dub has this gem.

Comics

 * Sandman's Merv Pumpkinhead: "Lady, I'm your worst nightmare. A pumpkin with a gun."
 * Which is based on the infamous subplot from Steve Gerber's run on The Defenders: "I'm your worst nightmare. An elf with a gun!"
 * Used as a joke in a Frank and Ernest strip where Ernest is being chased by a giant sausage that says: "I'm your WURST nightmare!"

Film
"Mr. Jigsaw: I'm your worst nightmare. Jack Colt: No, waking up without my penis is my worst nightmare. Mr. Jigsaw: Okay, alright, so I'm not actually your worst nightmare. But I am right up there."
 * Occurs in Rambo III.
 * Spoofed in UHF.
 * Also spoofed in Loaded Weapon 1:

"This probably actually refers to 48 Hours, where Eddie Murphy actually says the quote, making it a self-reference."
 * This is said in Mulan by Mushu as a Batman reference.

"Eddie Murphy, in a redneck bar: "I'm your worst nightmare... a nigger with a badge.""
 * Cop and a Half: "I'm your worst nightmare. An eight year old with a badge."
 * 48 Hours:

"Mikey: Who are you? Julie: I'm your worst nightmare!"
 * Spoofed in Canadian Bacon: The main characters use the line on a Canadian, only for the character to whom they say the line to describe their actual worst nightmare.
 * Look Who's Talking Too:

"E.L.F.S. Leader: We're your worst nightmare. Elves with attitude."
 * The Santa Clause:

"Kimberly: Power Rangers, this is Divatox. Divatox, this is your worst nightmare."
 * In Turbo: A Power Rangers Movie, Kimberly does this for the Rangers.


 * In The Lorax, O'Hare warns Ted that if the boy doesn't stop trying to find out about trees, he'll become his worst nightmare. Which, in his view, is Frankenstein's head on a spider's body.

Literature

 * Discworld:
 * Spoofed in Hogfather. Teatime uses this line on a guard, but his would-be victim wants to know which nightmare that would be. When it's clarified that he means, "The one where the man appears out of nowhere and kills you stone dead", the guard relaxes and points out that that nightmare isn't particularly scary. Then Teatime kills him stone dead.
 * Guards Guards has: "Someone out there was going to find out that their worst nightmare was a maddened Librarian. With a badge."
 * Sidorio from Vampirates describes himself as the sort of thing your worst nightmares "wake up screaming about."

Live Action TV
"Rita: Oh no, not you again! Tommy: Afraid so, Rita. Kimberly: We're like, you're worst nightmare."
 * The Titanium Ranger's introduction in Power Rangers Lightspeed Rescue
 * In the Mighty Morphin Power Rangers episode "White Light: Part 2", Kimberly delivers a variation to tiny!Rita as the Rangers re-seal her.


 * Used for comical effect in an episode of Herman's Head where Louise (Yeardley Smith, better known as the voice of Lisa Simpson) says it to a tyrannical boss two heads taller than her.
 * In the Mystery Science Theater 3000 episode "Teenage Caveman" the bots have a squirrel say this to the title character when he has rather more trouble catching than he should.
 * Tales from the Crypt: One story has a woman tangling with three CIA agents. She has killed two of them (not bad for a housewife) and faces the last agent, woman to woman. The housewife tells the agent, "I'm your worst nightmare. I'm a woman with balls!" The agents acts dismissive about it. ! She clearly wasn't kidding when she said that!

Music
""I am your sugar, I am your cream, I am your anti-American dream "I am your sugar, I am your cream, I am your worst nightmare, now scream!""
 * Emilie Autumn's "Gothic Lolita":

Tabletop Games

 * The tagline for the Dark Eldar in Warhammer 40,000 is "They are not your worst nightmare -- they are your EVERY nightmare!"

Video Games
""I am Cyan, retainer to the king of Doma. I am your worst nightmare...""
 * Cyan from Final Fantasy VI says this to the captain of the troops attacking his castle, and then defeats him in about two/three turns.


 * Lo Wang, the Shadow Warrior, is everybody's worst nightmare, at least according to himself.
 * "Welcome to the castle of nightmares! I'm your greatest nightmare!" So says the Final Boss of Shikigami no Shiro 3.
 * One of Anders' battle cries in Dragon Age II.
 * Soul Series: "I will show you the greatest nightmare!"
 * Bruce Irvin's only opening pose in Tekken.

Webcomics

 * This Bruno the Bandit strip.
 * Goblins: "...a goblin with a readied action and an elevation bonus.

Web Original
"Picard: Oh no, it's Jim! And he's slightly miffed."
 * Parodied on SF Debris where the evil Mirror Universe Star Fleet captains are arguing. Kirk says this line, leading Picard to shock him by asking if he's going to be raped by a giant spider. Picard is then severely underwhelmed by Kirk's actual intention of shooting him, pointing out that he has to worry about that all the time, and that you might as well say slipping in the shower is his worst nightmare.

Western Animation
"Doctor Destiny: I'm your worst nightmare. Batman: You have no idea what my nightmares are like."
 * From Justice League:

"Randy: Is somebody there? Skipper: Yes, somebody's here. Your worst nightmare! Randy: A flying coyote with eye laser beams? Skipper: Huh? No! Four angry penguins. Randy: Phew! Cause if coyotes ever develop flight and eye laser technology, it's game over, you know?"
 * The exact same sequence occurs between Payback and Bruce Wayne in Batman Beyond.
 * Batman: The Animated Series, episode 5, "Pretty Poison."
 * Transformers Generation 1 in the episode "War Dawn" when Optimus Prime is built from the wrecks of Orion Pax and steps onto the battlefield and quotes "You've caused enough destruction for one day, Megatron!" Megatron retorts with "I haven't even started!" then takes aim and says in a panic "You! Who are you?!" Optimus simply responds with "Your worst nightmare!" and promptly CurbStompBattles Megatron's drones. Doubles as a CMOA for Optimus
 * The Penguins of Madagascar, "Can't Touch This":

"I am your worst nightmare! I have a three-line phone and absolutely nothing at all to do with my time!""
 * Used to comedic effect on King of the Hill. Conspiracy nut Dale Gribble, who has a virtually encyclopedic knowledge of the ins and outs of government bureacracy, intimidates a worker at the Department of Motor Vehicles into providing better service by naming all of the worker's superiors in ascending order, then threatening to call them, using this exact line:


 * Star Wars: The Clone Wars: Said by Cad Bane to C-3PO in the episode "Evil Plans".