Missing

Missing is another one of Photo-Negative Gaster's three victims, who apparently seems to have suffered from his torment the most out of the three. Thanks to his experimentation with what it once was, it is now a hideous amalgamation whom should not be engaged at all costs.

Backstory
Missing's story begins in an AU called 'Underfell,' Sans is sitting at his post somewhere in Snowdin because his brother, Papyrus, has forced him to watch out for any humans. As to be expected, Sans would find this to be incredibly boring, as there have not been any humans for the past three hours, he was just this close to just leaving his post and complaining to his brother that there aren't going to be any humans passing by any time soon until he saw a strange figure out in the distance. It looked to be completely... white..? It wasn't even casting a shadow upon the snowy ground. "damn, is this what humans are like now..?" Sans would begin to think to himself as he had not seen a human in a very long time, the vague memories of the humans from the great Monster War were the only idea he had that that was what humans looked like. At least that was what he thought until the figure abruptly seemingly teleported in front of him, the figure was, in fact, not a human at all. It was in fact, a monster-looking entity whose colors have been completely inverted. Photo-Negative Gaster...

"oh- what the hell, i thought you were a human! get lost, my brother wont let me leave until i find one!" The figure did nothing, it stood completely still in it's place, not even the slightest bit of movement, almost statue-like. This would frustrate Sans by a great deal, he wasn't exactly known for being the most patient of monsters in the underground. "...so you want one of my good ol' fashioned ass-beatings, huh..? well, have at it!!" Sans would begin to summon a few bones from thin-air, about to pelt the figure with them before it suddenly began to reach it's hands toward the skeleton. After that, Sans' vision completely blacked out...

"...2 REBMUN YRTNE..." These monotone, metallic words had startled Sans awake, where he would find each of his limbs to be pinned to some kind of wall in a completely white room with a black floor by black hands with white holes in them. "wha... what the hell... where the fuck am i..." The oblivious skeleton would groggily mumble to himself. "...HTIW ETAREPOOC OT TLUCIFFID ...REHTAR EB OT DEVORP EH ,RETNUOCNE TSRIF NOPU '...LLEFREDNU' DELTIT ESREVINU A NI NOTELEKS FO DNIK SIHT FO NEMICEPS REHTONA DNUOF EVAH I..." The figure would continue to talk to itself aloud, whereas the skeleton in question could not understand it's inverted speech. "hey fuckface, how about a little english..?" Sans would rudely berate, the figure paying absolutely no mind to the skeleton's remarks. "...EVITCURTSED ...SSEL YLNO ,NEMICEPS SUOIVERP YM OT TCEFFE RALIMIS A EVAH YLLUFEPOH DLUOHS WON NEMICEPS SIHT HTIW OD OT DNETNI I TAHW..." The figure would explain to itself before another one of the hands materialized out of thin air, it looked much like the other four hands that were pinning Sans to the wall, only with far sharper fingers. The hand would shape itself into a sort of pointing formation before gliding towards the skeleton's head, puncturing it with incredible ease. This would generate quite a bit of screaming and swearing that would give anyone's grandmother a stroke from him, he could suddenly feel some sort of liquid filling his hollow skull. The strange liquid would begin to deform the skeleton's bone structure, such as detaching his arms from his body, which would both fall straight through the floor, almost like a couple of sticks falling into a body of water, his legs becoming unnaturally stretched to nearly more than twice their original length, his eye socket, mouth, and nosehole being sealed up with excess bone marrow, and even an extra arm growing out of the unsealed eye socket. "...ALUMROF YM ESIVER OT YRT I ELIHW YRESIM S'TI FO TUO NOITAMAGLAMA SIHT TUP LLAHS I ,LLEW HO ...SNOITALUCLAC YM NI WALF FO TROS EMOS EDAM EVAH I TAHT RAEPPA DLUOW TI..." The figure would say to itself before disappearing as another hand materialized from above the now deformed skeleton, only this one was far larger than any of the other hands. A black glow would begin to eminate from the hole of this gigantic hand before shooting down a massive black beam, striking the amalgamation at nearly pinpoint precision. The beam would continue to blast for a solid ten minutes before finally dying out, the hand completely disappearing. All that was left of Sans was a charred, crusted up deformed skeleton...

...until the remains began to move it's eye arm. It turns out that the blast had not been enough to completely eradicate the amalgamation. It was now completely devoid of any emotion except for one... RAGE... The amalgamation would begin to sink it's eye arm into the white walls, tearing a good chunk out of it before putting it on it's face as if it were some sort of one-eyed mask so nobody else could see what kind of deformed atrocity that it's face had become after these events. The chunk would begin to slowly decay as it crumbled on it's face, even gaining a sort of reddish glow to it. The glow, of course, eminating from the amalgamation's sheer rage. With that being done, it would teleport from the strange room, the amalgamation had successfully escaped...

Inverted HP
Photo-Negative Gaster's victims usually tend to gain this ability once he's finished experimenting on them. The negative HP behaves as positive HP, meaning that normal attacks only make the owner of said ability stronger, while healing attacks are dangerous to them.

Decaying Grab
Missing will use it's arm emerging from his eye socket to grab anything that it can get it's hands on, once an object has been grabbed, it will begin to slowly decay, normally until inevitable death. Missing has absolutely no control over this ability, the arm quite literally has a mind of it's own. The decaying effect usually will not completely kill beings that are of High Multiversal status or higher, this does not mean that they are exempt from the decay effect entirely, however. Low Omniversal beings and higher are completely unaffected by the decay effect. The more powerful the target is, the slower they will decay.

High-Pitched Frequencies
If it finds the current situation that it is currently in to be a necessary time for it, Missing will project very loud high-pitched frequencies from it's mask, being around 352 decibels and an ungodly 4.7 TRILLION Hertz. Though this move doesn't affect Missing itself, hearing any of it's frequencies as a mortal human being for even a mere 0.02 microseconds will be enough to completely rupture every vital organ in their body as well as shatter their skull. Missing can only produce these frequencies for ten seconds at a time before having to rest it's mask's energy, recharing this move again may take around two to twenty-eight hours.

Teleportation/Universal Travel
While it can no longer use it's bone or Gaster Blaster attacks due to the experimentation performed on it, Missing can still teleport quite efficiently. So efficiently to the point that it can actually travel to other universes, though it usually doesn't like to be seen by any other living thing due to how deformed it became from the experiment, so it tries to stay out of everyone and everything's sight.

Trivia

 * Missing is Photo-Negative Gaster's second victim.
 * Much like Fade, Missing cannot eat any kind of food without losing HP.
 * Though it cannot do that anyway due to his mouth being sealed up by bone marrow.
 * Missing has nigh-indestructible bone marrow, meaning that not even a head-on collision with a bullet train would even bring a scratch to it's bones.