Specimen pod
A specimen pod was a vertical glass prison for living organisms.
History
Steven Moffat owned a specimen pod in which he imprisoned live "specimens" to study when writing his stories. It was kept in his "writing lair" in the volcano beneath 221B Baker Street. When Christel Dee broke in (wishing to steal the top-secret scrips for Series 9 of Doctor Who), the pod was empty. She recognised it immediately.
After Moffat found the interloper hiding in a cabinet, however, he ordered her to put on her Tenth Doctor cosplay outfit and then locked her in the specimen pod, from which she anxiously delivered the closing lines of that week's episode of The Fan Show while expressing uncertain hope that Moffat would eventually let her out. Moffat left the room, switching off the lights behind him. (NOTVALID: '’Stealing Series 9 Scripts)