The Masque of the Red Death
The big, black, creep clock is located in the black room, so it's not that hard to guess that it's meant to be a symbol of death. More precisely, it's a symbol of the passing of "the Time that flies" (5), and the inevitability of death. Its eerie chiming on the hour is a regular reminder to the revelers that their lives are drifting away with the time, and that death is approaching. Of course, the effect is enhanced even more by that way the clock has of stopping all the dancing and music – in short, all the life – of the party, and making everyone laugh nervously.