Bobby leaves in New Mutants #99 after his father's death, with Gideon drawing him toward his family's business responsibilities.

Bobby leaves in New Mutants #99 after his father's death, with Gideon drawing him toward his family's business responsibilities. From Bobby's position, this is a chance to deal with something outside the team and take responsibility for the life his father has left behind. From the reader's position, Gideon's involvement is already a reason not to take that arrangement at face value. The timing matters because the New Mutants are about to become something else. Sam stays with the group. Bobby doesn't simply stand beside him as another original member of the new field team. Those two friends are now going in different directions. Sam is staying with Cable's operation, while Bobby is leaving to deal with family business and Gideon. After watching them grow up together through this whole series, that split deserves more attention than just saying Sunspot used to be a New Mutant.