Mutant 2099 is not actually from the 2099 timeline, the 2099 is his registration number, and he is from Earth-2992, a reality in which mutants have been outlawed. Each mutant is identified at birth, given a registration number, and prescribed drugs in order to keep their mutant power from ever manifesting itself.
In his youth Chad, while meandering about the bowels of a futuristic New York City stumbles upon a helpful, albeit odd, ally. He comes into possession of a preserved brain, later to reveal itself to be the ingenious Reed Richards. Richards provides Chad with a placebo duplicate to his pills allowing his powers to manifest themselves.
Together the two, Richards implanted into a cybernetic body resembling his former partner Ben Grimm, fight off such villains as the Mole People or work to protect the innocent from being injured in close-minded fights between rogue mutants and sentinel enforcers.
Mutant 2099 resembles Spider-Man greatly with a form-fitting blue body suit and insect-like glasses, though his hair is allowed out of the top of the piece. His powers even mirror those of Spider-Man. He uses his telekinetic abilities to augment his strength and agility and a partial precognition ability to further increase his agility.
He is even shown at times moving about in a similar fashion to Spider-Man by swinging from building to building on an unknown substance.
On Earth-6215 Mutant 2099 is a member of the League of Losers a group of Super-Heroes remaining on Earth after nearly all of the have been wiped out.