Carl King was once a cruel high school student who bullied Peter Parker for years. When Peter was bitten by the radioactive spider that would turn him into Spider-Man, Carl was there as well and saw it happen. He later discovered the impact of this bite when he saw Peter leaving his Aunt May's house dressed in his Spider-Man outfit. Desiring the same abilities, Carl broke into the nuclear physics exhibit they'd attended and stole the spider that had bitten Peter. It was long dead though at this point and couldn't bite Carl anymore, so he did the next best thing. He ate it. Over the next few days, nothing really seemed to change for Carl until one morning he instinctively expelled a spider from his body that ate his mother from the inside out and took control of what was left of her body. The radioactive spider had multiplied into numerous spiders and ate Carl from the inside out, his consciousness spreading into them. He had become The Thousand, a sentient swarm of spiders.
After eating his mother, Carl was curious if he could do the same thing again, and he soon did so to his father. Over the following years, Carl ate nearly a dozen people a year - mostly homeless people and even some children - gaining strength with each person he devoured, biding his time until he could be strong enough to kill Spider-Man.
Major Story Arcs
The Coming of the Thousand
After witnessing Spider-Man in a fight against the Rhino, Carl King convinced himself that it was time to take for himself the glamorous superhero life that Parker had robbed him of. He followed him to the Daily Bugle and waited until almost everyone had left for the evening, and then ambushed the young secretary Jess Patton that Peter had talked to earlier that day. He quickly devoured her from the inside and used her remaining skin to assume her identity.
Disguised as Miss Patton, Carl sought out Parker and took advantage of his good nature with a bogus sob story, persuading him to take "her" back to his apartment. Carl then took his chance to strike. Confused by Miss Patton's attack, Parker was easily taken off-guard and began being trounced by Carl's relentless assault, barely having the time to change into his Spider-Man costume.During the fight, Carl bit Parker, injecting a poison into him that caused him to black out. Parker soon found himself tied up and at the mercy of the Thousand.
Carl took the time to happily taunt Parker after all these years, gradually letting him know who he was until Parker figured it out. He then told him his story of how he went from sadistic bully to murderous monstrosity. Carl then fully revealed himself as the Thousand by having his swarm of spiders discard Jess Patton's skin and prepare to take over Parker's body so that he could finally become Spider-Man. Instead, the building supervisor Mr. Ambrose arrived to complain about the noise, interrupting Carl's meal and causing him to become his next victim. Now in the body of Mr. Ambrose, Carl continued telling his tragic origin story. Parker became especially horrified when Carl talked of all the people he killed over the years to sustain himself. Luckily, Carl's lengthy gloating gave enough time for his poison to wear off on Parker and he freed himself from his captivity. Another vicious melee ensued with Carl still managing the have the upper hand. He was momentarily taken aback though when Parker stated that he was no longer afraid of him and his intimidating ways. Parker began pounding away at Carl until he was violently thrown into an electrical box. Carl pursued and - despite Parker's warning - delivered a punch directly into the box and electrocuting the Thousaned right before Parker's eyes.
One of the spiders survived the experience however and vowed to bide its time and seek vengeance on Spider-Man once again. He would have escaped, if not for the misstep of a random passerby who stepped on the spider and crushed it. Whether or not any other spiders of the Thousand survived is yet to be seen.
Powers & Abilities
The Thousand has powers and abilities similar to the villainess, Miss Arrow. He can become any person he wants to by eating that person from the inside out and taking on their skin. Since he can change bodies at any time, his height, weight, and other physical features are all variable. The Thousand has all the powers and abilities of Spider-Man, even while in a host's skin. His consciousness is spread throughout the swarm, so if one spider out of the Thousand's swarm survives, he can survive and multiply.
He is also immune to Spider-Man's spider-sense and can deliver poisonous bites with his spiders that are strong enough to incapacitate a full-grown human being.