Trick-or-treating

 was a tradition practised once a year on Halloween night. Children wore Halloween costumes and went door to door receiving candy. Trick-or-treating was practised on Earth (PROSE: Forever Autumn) and Verticulus. (COMIC: Wholloween)

History
In 2007, Rick Pirelli went trick-or-treating with his friends Scott Beaumont and Thad Steiner. They planned on watching scary movies afterwards, but the trick-or-treating was brought to a premature close when Scott vomitted.

In 2008, Rick, Scott, and Thad planned on going trick-or-treating, but weren't able to due to the Hervoken trying to destroy their hometown. (PROSE: Forever Autumn)

On a 30 October in the 2010s, four trick-or-treaters approached Hector and asked him for candy. Also on this day, an elderly man was affected by the Cerebravore emotion field and became terrified of a trick-or-treater dressed like a superhero. (COMIC: Revolutions of Terror)

The Eleventh Doctor and Amy Pond once encountered two trick-or-treaters on the planet Verticulus. They were disappointed when they got Jammie Dodgers instead of baby brains and they covered the Doctor's TARDIS in toilet paper. (COMIC: Wholloween)