To accommodate lodgers, Procrustes
Would stretch them or chop as he must. “He's
“Got a comfortable bed,
“If you just keep your head,”
Said the blithest of recent adjustees.

Based on the suggestion: “Procrustes”

If you're not familiar with this Greek myth, Procrustes claimed to have a special bed that exactly fit anyone who spent the night in it.  This was not a magical property of the bed, but rather an indication of Procrustes' evil nature, as he would torturously lengthen or shorten the person until they fit the bed.