The event began on October 18, 2006, and ran through November 2, 2006.
During this event, players were able to 'Trick or Treat' by clicking on mission doors in the various zones. Players could only click once per 60 seconds, and after a particular door had been clicked on, neither the player nor anybody else could use it for 30 seconds. If a door was successfully knocked, then either a treat was awarded usually in the form of a random inspiration or costume salvage, or else a trick, which would spawn various enemies in the immediate area.
Players had to Trick or Treat in a zone that matches their current effective level (See list below), or the doors would not give tricks or treats. Sidekick/Lackey and Exemplar/Malefactor could be used to allow Trick or Treating to work, and the auto-exemplar of PvP zones meant that they would work for anyone high enough to enter them (except for Recluse's Victory, which has no functioning mission doors.)
During the event, the entire game was locked in nighttime mode. This was not just a visual effect. All aspects of the game that depend on a day/night cycle were locked to the night side during the event. Enemies that only spawn at night were spawning continuously during the event. Banisher, The Slayer, and Haunted badges (Hero side) and Pirate and Spectral badges (Villain side) are examples of badges for which hunting was be much easier during the event.
The event ran in all zones in the game except Recluse's Victory, The Hive, Cascade Archipelago, The Chantry, and The Storm Palace. The few zones where the event is not running are all zones for at least level 40 characters, so for any characters below level 40, literally every single accessible zone will be running the event.
Temporary Powers Edit
One of the treats is the Rock temporary power. It is a one use, ranged attack that does minor smashing damage. Matt Miller was the developer behind this homage to It's the Great Pumpkin, Charlie Brown. 
Free Costume Slot Edit
The event introduced the ability to unlock a free costume slot on any character. Which slot it opens depends on how many costume slots you have already unlocked. Costume slots are awarded incrementally...a level 1 will be awarded their second slot, while a level 50 with all four previous costume slots unlocked will unlock a fifth. This reward did not include a free costume change token; unless you have free costume change tokens left over from previous awards, you will have to pay normal influence or infamy costs to change the costume in this new slot.
To unlock this slot a player needed to gather one each of the four types of Event Salvage that can be found through "Trick or Treating". You need one each of Statesman Mask, Lord Recluse Helmet, Back Alley Brawler Gloves, and Hamidon costume. All four then need to be brought to the appropriate Halloween contact for the character's game. Granny Beldam for villains and Annah for heroes. The contact will then unlock the free slot. Note that the devs have said  that the contacts will remain in the game, so that, while new costume salvage cannot be earned after the event, existing costume salvage may still be turned in. There was a 35% chance of any Treat being a piece of event salvage, with even chances for which of the four types of event salvage is received.
Event Salvage Edit
Back Alley Brawler Halloween Gloves Edit
These are rubber Back Alley Brawler gloves, perfect for a Halloween costume. Their manufacture makes it difficult to perform simple tasks like opening doors. Heroes can take this to Annah in Croatoa, while villains can take this to Granny Beldam in Nerva, for a reward.
Statesman Halloween Mask Edit
This is a Halloween mask of the famous hero Statesman. It's made of cheap plastic, and the flimsy string probably won't last through the night. Heroes can take this to Annah in Croatoa, while villains can take this to Granny Beldam in Nerva, for a reward.
Lord Recluse Halloween Helmet Edit
This is a Halloween mask of the infamous Lord Recluse. It's made of smelly rubber, and wearing it makes you all sweaty and hard to find your breath. Heroes can take this to Annah in Croatoa, while villains can take this to Granny Beldam in Nerva, for a reward.
Hamidon Halloween Costume Edit
The most popular Halloween costume among the kids in Paragon City is that of Hamidon. This simple costume is made from coloured plastic wrap. Many kids like to put action figures of their favourite heroes inside the wrap, pretending they are 'raiding' for 'Hami-O's' Heroes can take this to Annah in Croatoa, while villains can take this to Granny Beldam in Nerva, for a reward.
| Hallow Spirit|
You have helped defeat a manifestation of Eochai, king of the Fir Bolg.
You have defeated 20 of the nefarious Vampires who rose from their graves on Halloween.
You have defeated 20 ghosts, spirits who have not rested since their original death.
You have defeated 15 werewolves, supernatural creatures created through the disease of lycanthropy.
| Dead Head|
You have defeated 50 zombies, the walking flesh of the recently dead.
You have defeated 75 witches, sorcerous crones who use dark magicks.
Trick or Treating only worked if the palyer was in a zone with a level appropriate for their current combat level. The following are the appropriate levels for various zones:
- 01 - 11 Atlas Park
- 01 - 11 Galaxy City
- 05 - 15 Kings Row
- 05 - 15 The Hollows
- 07 - 15 Perez Park
- 10 - 20 Steel Canyon
- 10 - 20 Skyway City
- 11 - 20 Boomtown
- 14 - 20 Faultline
- 20 - 30 Independence Port
- 20 - 30 Talos Island
- 20 - 30 Striga Isle
- 20 - 30 Terra Volta
- 21 - 30 Dark Astoria
- 25 - 35 Croatoa
- 30 - 40 Brickstown
- 30 - 40 Founders' Falls
- 30 - 40 Crey's Folly
- 33 - 40 Eden
- 40 - 50 Peregrine Island
- 40 - 50 Firebase Zulu
- 40 - 50 Rikti Crash Site
- 01 - 10 Mercy Island
- 05 - 15 Port Oakes
- 10 - 20 Cap Au Diable
- 20 - 30 Sharkhead Isle
- 25 - 40 Nerva Archipelago
- 30 - 40 St. Martial
- 40 - 50 Grandville
PvP (Both) Edit
Since all PvP zone automatically Exemplar anyone entering to a specific level, anyone entering the zone is brought to a combet level appropriate to the zone, so all zones are appropriate for Trick or Treating for anyone of a high enough level to enter the zone.
Note: none of these groups counted toward the non-Halloween badges available in the game normally. For example, these Fir Bolg do not count towards the Pumpkin Master/Mistress badge.
The Coven is made up of witches also seen as the Cabal enemy group found in Croatoa. Note that this group is the most visually different from their normal in-game spawns of any of the Halloween mobs. The Cabal is primarily colored in shades of grey and black, while the Halloween Coven is much more colorful.
Fir Bolg Edit
Unseelie Court Edit
Eochai and Jack in Irons Edit
There was a zone spawn of either Eochai or Jack in Irons in every zone in which the event is active. Once one is defeated, another of the two would spawn in the same zone within a minute or two. For each spawn, there was a 90% chance that it would be Eochai, and a 10% chance that it would be Jack in Irons. Additionally, Jack in Irons only spawned in level 20 and up zones.