[[caption-width-right:275: ''Rest. in. Peeeeeeeeeeeeeeeeeace........'']]

Considering that he's "The Deadman" and all, along with having a 20 year career in WWE, The Undertaker is all about the Nightmare Fuel, and has racked up quite a fair share of it over the years.

* The Undertaker's debut back in 1990, which signaled a major paradigm shift in the way sports- entertainment would be presented in the years to come. [[SeinfeldIsUnfunny As cheesy as the gimmick may seem nowadays]], in the candy-colored circus that was WWE during the Reagan/Bush era the 'Taker gimmick was unique - and frightening. His theme, "Dark Side", was in the beginning much less elegiac and a lot more minimalist and creepy - literally like the music played in a funeral home chapel. 'Taker also [[SilentAntagonist never spoke]] and literally tried to kill his opponents, usually by choking them. Add to that Paul Bearer's [[ButNotTooWhite pasty white skin]] and unnaturally high voice, and it was undeniable that the Undertaker's appearances truly were something to fear.
** Scott Keith even admitted that the crowd reaction at Survivor Series'90 was something very unprecedented..and if you look on the faces of ''adult'' fans in the crowd, legitimate fear is very visible. ''No one'' knew what to make of this.
* Anything that involves his "return" after being "buried alive".
* The Undertaker's theme is considered NightmareFuel due to it beginning with the loud eerie ringing of a church bell like the beginning of AC/DC's Hells Bells but scarier, then crescendoing into the creepiest rendition of Chopin's Funeral March ever, and the rest of the music sounds like something out of a Franchise/ResidentEvil game. Scary enough for ya?
** Though whenever 'Taker is working as a face, that church bell veers away from this trope into MostWonderfulSound.
** The sound of the gongs itself, even though it is part of the [[SugarWiki/AwesomeMusic Music Of Awesome]] yet when placed in the right time, it sends chills.
* Undertaker locking Wrestling/UltimateWarrior into a [[http://www.youtube.com/watch?v=rNg95xuwuCs casket.]] Even worse, it went on and on, with various officials trying (and failing) to get Warrior out of the casket. When they finally did, it was revealed that Warrior had torn up the coffin in a desperate attempt to get out. Creepy stuff for a show aired on Saturday afternoons.
** [[HarsherInHindsight Made even worse]] with the Ultimate Warrior's sudden passing at the age of 54. And the Warrior once said that he would die once he saw Undertaker's streak ended...which it did two days before his death.
* Anytime he pulls people down below the ring. He once did it to Kane, his half-brother, and the look on the Big Red Machine's face was of pure agony.
* The ''Tombstoned'' magazine special with the cover of him looking like a corpse in a coffin. Some sellers were given the heebie jeebies about it and expressed concern over its sale.
* Three words: [[NotMyDriver "Where to, Stephanie?"]]
** Three more words: "Buckle up, Teddy."
* His mind games with Randy Orton leading up to Hell in a Cell at [[Wrestling/ArmageddonWrestling Armageddon '05]]. Ranging from appearing in a mirror than vanishing, pretending he was a wax figure in an open coffin before choking Orton, ''possessing'' Josh Matthews....the list goes on and on.
* His feud with Ken Kennedy in 2006. The lead-up to their First Blood Match in Survivor Series has Undertaker state their match...and then blood starts ''raining down on Mr. Kennedy'' not unlike Gangrel's blood baths. Then, lead-up to their Armageddon Last Ride Match has Undertaker--who was about to be run over by a hearse--somehow teleporting to ''the passenger's seat'' of said hearse.
** And speaking of Armageddon, after Undertaker takes a huge fall from the entrance, Kennedy drags the Phenom's body to the hearse and is about to drive it out...cut to a camera in the hearse showing Undertaker ''sitting right back up behind Kennedy!''
* During his [[FanNickname Bikertaker]] days, Taker had no problem giving out [[NoHoldsBarredBeatdown beatdown]]s to people. Some examples include:
** Getting [[Wrestling/RicFlair Ric Flair's]] attention by pulling his oldest son, David, [[http://www.youtube.com/watch?v=ZWKBnqn87yM into a locker room]] and proceeding to [[AdultFear beat the tar out of him]]. One line in particular toward the end of the segment really sticks out:
---> '''Taker:''' (to David) Hey, [[KickTheDog don't you have a little brother]]? No no no...[[WouldHitAGirl you have a]] ''[[Wrestling/CharlotteFlair sister]]'', [[WouldHitAGirl don't you]]? ({{Evil Laugh}})
** Attacking Wrestling/{{Jeff Hardy}} after he's been [[KickTheDog handcuffed to the ropes]], while {{Wrestling/Raven}} forces a horrified Wrestling/{{Matt Hardy}} [[http://www.youtube.com/watch?v=qrok_b2CklQ to watch]].
* Anyone watching Elimination Chamber '10 on WWE Network would be fooled by the commentary about how he's clearly ready to go, not wasting any time getting into the match. What you didn't see during the split second cutaway was Undertaker effectively was stood right on top of some lit pyrotechnics. Anyone looking at unedited footage is able to see him stagger for a moment, his jacket briefly on fire, before he runs to the ring to get into his pod. He IS not wasting any time, but it's nothing to do with how ready for the match he is, he's suffering some potentially bad burns!
* This one has been covered in the [=CMoA=] territory, but Undertaker's alleged threat to Wrestling/ShawnMichaels that he had better lose the championship to Wrestling/StoneColdSteveAustin at Wrestlemania 14…or else. Considering Taker was sitting backstage watching the match with his fists taped, one gets chills thinking of what he would do to Michaels. Consider that Undertaker is seven feet tall, and over three hundred pounds of angry muscle...
* His RoaringRampageOfRevenge on Vickie Guerrero. [[SarcasmMode Highlights]] included (1) locking her in her office for an entire ''[=SmackDown=]'' before finally invoking LightsOffSomebodyDies at the end, (2) threatening her with his specialty of BuriedAlive, and (3) using his LightFlickerTeleportation to subvert her HopeSpot ZergRush of Chavo Guerrero and The Big Show. Just a clear reminder of why you shouldn't get on the bad side of a giant KungFuWizard as much as she had. Oh, and his genuine-looking DeathGlare just before Tombstoning her: https://www.youtube.com/watch?v=-tjEBgAH9ZA