Howdah

A howdah was the carrier on the back of elephants in India. (TV: "The Watcher") It was strapped onto the beast and was canopied, but with open sides. Their box-shaped design usually allowed for two people to ride next to each other. They were often elaborately decorated, typically with tassels.

The First Doctor mentioned to Steven Taylor that if the TARDIS's chameleon circuit was functioning correctly, the TARDIS would possibly take the form of a howdah if they landed in India. (TV: "The Watcher")

The Tenth Doctor and Donna Noble used a howdah when they travelled by elephant with Gandhi. (PROSE: Ghosts of India)