Christmas crackers were an integral part of Christmas parties. They were pulled by two people and there was a resultant bang. They commonly contained novelty gifts and hats, known as Christmas hats.
The Tenth Doctor once pulled crackers with Rose and Jackie Tyler while dining with them at Christmas. (TV: The Christmas Invasion)
On Christmas Eve, the Eleventh Doctor pulled crackers with the Pettigrew family and Kazran Sardick as part of their celebrations. He hid a playing card in one. (TV: A Christmas Carol)
Clara Oswald had a cracker at her family's Christmas celebration, but later took it to an aged Eleventh Doctor on Trenzalore. (TV: The Time of the Doctor)
In a dream crab sequence, the Twelfth Doctor and an elderly Clara shared a cracker. (TV: Last Christmas)
On Puxatornee, Professor Capra asked the Seventh Doctor and Mel if they wanted to pull a cracker. (AUDIO: Flip-Flop)