Bunk bed
From Tardis Wiki, the free Doctor Who reference
A bunk bed was a type of bed which the Eleventh Doctor found "cool". Describing it as "a bed with a ladder", he added that "you can't beat that." Amy Pond and Rory Williams' bedroom aboard the Doctor's TARDIS had a bunk bed but when the Doctor rebuilt the room, following a mass deletion of all the bedrooms, he agreed to provide them with a single bed. (TV: The Doctor's Wife)
On the Sea Devil Earth, the human slaves slept in bunk beds. (COMIC: Alternating Current)