The Colour of Magic- The Luggage (Wikipedia)
The Luggage is a large chest that follows Rincewind literally wherever he goes—even onto Roundworld, which Rincewind initially only visited virtually. It is made of sapient pearwood, a magical, intelligent plant that is nearly extinct, impervious to magic, and only grows in a few places outside the Agatean Empire, generally on sites of very old magic. As such, whilst considered oddities on the Hubland continent, such chests were commonplace in the Agatean Empire. It can produce hundreds of little legs and move very fast if the need arises. It has been described as “half suitcase, half homicidal maniac”.