Matchbox

A matchbox was a container used to hold matches. After they had been miniaturised, Ian Chesterton and Susan Foreman found a giant matchbox in Arnold Farrow's garden. Ian fell into the matchbox, which was then picked up by Farrow. (TV: Planet of Giants)

A man claiming to be the Spy Master shrunk O using a Tissue Compression Eliminator, and kept him in a matchbox. He showed this to the Thirteenth Doctor when boasting about kidnapping O and adopting his identity. (TV: Spyfall)