Stepping Disks

Magical portals of white light that originate in Limbo and can transport any who step into them anywhere in time and space. Normally, the portals pop in and out of existence in Limbo, and their termini are random, making traveling through them foolhardy at best. However, with appropriate knowledge, a magician can learn to control the disks. The best user, though, was Magik, whose mutant power was to mentally control the disks and have them appear wherever she was, and go wherever she wanted. She could also manipulate the size of the disks to accomodate many other people. It was actually through one of the stepping disks that appeared on Earth that young Illyana Rasputin fell, leading her to her apprenticeship with the sorcerer Belasco. As a member of the New Mutants and ruler of Limbo, Magik used the disks as her personal transportation devices. Magik II has also learned to control the disks, though she does not have the innate control of her predecessor. She does, however use the Soulsword in conjunction with her magic to open the portals.

Note: In the Earth X timeline it was revealed that Limbo may actually be the amalgamation of all of Doctor's Doom's time machines from all the various timelines in which he (and later his descendant Kang) existed. If true, then the stepping disks might simply be pockets of the structure of Limbo in which the original "time machine" nature comes through.