Timeslip is a superheroine in the Marvel Universe and is former member of the New Warriors.
Rina Patel is an Indian mutant, born with special, superhuman abilities. Initially her only known special ability was to completely swap her current consciousness with her consciousness from any other point in her life, past or future.
As a college student, Rina was seen "time-swapping" to when she was four years old as an escape from studying. At the same time, her four-year-old consciousness was time-swapped to her college-age self, causing the child version of herself to panic. Suddenly Rina's current self was ripped to another time, a bewildering vision of herself in a superhero outfit talking with the New Warriors in their Crashpad headquarters. The short episode passed, and a confused Rina decided to pay little heed to the strange future that seemed to be in store for her.
In her next appearance, Rina once again time-swapped to her own near future and found herself holding what appeared to be a dying Speedball/Robbie Baldwin in her arms.
Concerned for Robbie's welfare, Rina began making concerted efforts to contact and warn him of her frightening future vision. However, Speedball did not take her warnings seriously, assuming she was a "super hero stalker" of some kind. Ultimately Rina found Carlton LaFroyge (Hindsight Lad) and convinced him of her sincerity and special abilities by pushing him out of the way of an oncoming truck. This involved Rina warping time so that she seemed to be moving super-fast, an ability she had not previously realized she had.
Trying to help Rina (and her warnings) be taken seriously by the New Warriors, Hindsight Lad designed a superhero costume for her, dubbed her Timeslip, and arranged for her to meet with the team while showing off her time-warping abilities. Even after this demonstration and Rina's impassioned warnings, Speedball was still dubious about her predictions, while the rest of the team did not know quite what to make of her. However, Timeslip's persistence convinced the Warriors to keep her around as they tried to figure out how to prevent her future vision of Speedball's death from coming to pass.
Over time it became clear that Timeslip's visions always came true exactly as she saw them, and Robbie's apparent death was no exception. When the Sphinx appeared and, brushing the Warriors aside, killed Speedball in cold blood. He died in her arms, just as she had foreseen.
However it was ultimately revealed that the Speedball who died in Rina's arms was in fact an exact duplicate who had been created in the year 2092. This advanced biological construct was designed to take Robbie's place as a sleeper agent, tasked with preventing a deranged time-hopping villain, Advent, from rewriting future history to his liking. The Sphinx intentionally killed this Speedball duplicate because "he would have failed" to stop Advent. This brutal and seemingly senseless act of murder set in motion a chain of events that drew Rina into the New Warriors team and allowed her to stop Advent herself, saving the future and the rest of the New Warriors.