Space loop

A space loop was a phenomenon similar to a time loop, but in space instead of time. The Third Doctor and the Master were once caught in a space loop when their TARDISes materialised inside each other. (DW: The Time Monster)

The Eleventh Doctor and his companions Amy Pond and Rory Williams were also once caught in a space loop when the Doctor's TARDIS accidentally materialised inside itself. (DW: Space / Time)