Magnetic hobble-field

A magnetic hobble-field was the radiation generated by a magno-grab. Such a field once ensnared the Doctor's TARDIS and nearly caused the ship's destruction. It was activated, and later de-activated, through the use of a magno-grab remote. According to the Eleventh Doctor, such radiation could normally be countered by shield oscillators, but his were disengaged at the time the field was generated, as he had put the TARDIS on basic mode. (TV: Journey to the Centre of the TARDIS)