What would happen if....
..you took a polystyrene object, decorated it with bright, permanent markers, put it in a net bag and sent it to the bottom of the Hess Deep? Answer, your object shrinks to a fraction of the size due to the huge pressure exerted on it by the water.
Meet Polly, she was rather beautful before her dive, when she surfaced I realised that I had used washable pens-doh!
The cups were attached to the IT housing in net bags