CAT: What IS it??
Rimmer: It´s a rent in the space-time continuum.
CAT: What IS it??
Lister: The stasis room freezes time, you know, makes time stand still. So whenever you have a leak, it must preserve whatever it´s leaked into, and it´s leaked into this room.
CAT: What IS it??
Rimmer: It`s singularity, a point in the universe where the normal laws of space and time don´t apply.
CAT: What IS it??
Lister: I´s a hole back into the past.
CAT: Oh, a magic door! Well, why didn´t you say?