Temporal fission

Temporal fission was a Time Lord concept once used by Rassilon to send numerous incarnations of the Doctor home to their respective points of origin in space and time.

According to varying accounts, this process either resembled multiple versions of the Doctor's TARDIS splitting off from the Fifth Doctor's TARDIS (TV: The Five Doctors) or multiple Time Scoops branching off from the TARDIS to return the travelers home. (HOMEVID: The Five Doctors, 1999 special edition)