Beverly Crusher's old mentor, the first person to vanish when she became trapped in a shrinking warp bubble universe.
Dr. Dalen Quaice was an elderly physician who had been Beverly Crusher's mentor. In Remember Me he came aboard the Enterprise-D to travel home, having recently lost his wife, and Crusher tried to support him.
Shortly afterwards, Quaice was the first person to disappear, and soon others followed, though nobody but Crusher remembered them. She had been trapped in a warp bubble created by an experiment of Wesley's. With the Traveler's help, Wesley brought her back to the real universe, where Quaice and the others had never actually vanished.