On October 20, 2010, the Halloween Trick AND Treat event was started, and the Haunted Terrortories (not a typo; but a bad pun :p ) location was opened.
First, you should click on "Friends" and visit your friends profiles, and clicking the "Trick or Treat" button. You may get a Treat, and therefore 6 Candy Corn cheese, or a Trick, and therefore 6 Ghoulgonzola cheese.
You can also set whether to Trick or Treat friends who visit your page by going to your own profile (click on the shield). It is recommended that you change this to 'Trick'.
Note that it is set to Treat by default. Thus if most of your friends have not switched, you may find yourself with a surplus of Candy Corn cheese; try asking some of your friends to switch to Trick. On the other hand, if all/most of your active friends have already switched to Trick, try visiting friends who have not played in a while (i.e. in the last pages of your friends list) to get some Treats!
You can go "trick or treating" on up to 10 profiles a day. Each day begins on midnight GMT. The MouseHunt Timer is useful for keeping track.
Note that the Haunted Terrortories are only open for Recruit and up. If you're still a Novice, don't despair; the special cheeses have a high attraction rate in the Meadow, so feel free to use them there until you reach Recruit! What's more, they're effectively free, so you save gold buying cheese!
Note the status bar when you enter the Haunted Terrortories. This shows your progress through the three sub-locations: the Corn Field Maze, the Haunted Manor, and the Pumpkin Patch.
You need to catch mice with both special cheeses to advance to the next sub-location (this is done automatically; no travel is required). Each catch with Ghoulgonzola fills up the Mice Tricked bar, and each catch with Candy Corn fills up the Mice Treated bar.
Note that if you surpass the requirement for one side without fulfilling the other, the boxes do not fill past the next location symbol; and your cheese is wasted. For example, if you fill up the 10 "Mice Treated" boxes before the Haunted Manor symbol before filling up the 10 "Mice Tricked" boxes, any mice you continue to catch with Candy Corn cheese do not further contribute to your progress.
If you're short on special cheese, you can switch to hunting with regular cheese. Mice here occasionally drop Candy Corn or Ghoulgonzola cheese that you can continue to hunt with.
Gifts are now available (under the Friends menu), and what's better, they're free! However, you can only accept and send a number gifts a day (beginning at midnight GMT) based on your rank, so choose wisely! Ask your friends if there's a specific gift you want (of course, you should return the favor if they ask).
The Pumpkin Treat Baskets are of special note; they may contain event cheese, or one of these four limited edition collectibles not available by any other method:
Empty Candy Wrapper
Lovable Bat Plushie (can be "squeezed" in your Collectibles list! Awr!)
Here's a list of tips for each sub-location:
Corn Field Maze
This sub-location has indigenous mice (dressed for the occasion!), which should be able to be caught by most traps. It also features the Hollowhead mouse, which is an event mouse you may have already caught if you were playing on previous Halloween seasons; if not, this is your chance to get one! Try using your luckiest setup to increase loot drops.
Mutated Grey mice drop Candy Corn cheese, Mutated White mice drop Ghoulgonzola cheese, and Hollowhead mice may drop either or sometimes both.
You need 10 mice tricked and 10 mice treated to advance to the next sub-location.
Tougher mice from the Shadow Clan group appear. Thus it is recommended to switch to your strongest Shadow or Arcane trap, if you have one.
If you don't have one, don't worry; all mice from the Corn Field Maze still exist, and the event mice can still be caught by physical traps.
The first new event mouse appears, the Zombot Unipire Mouse. It is a little uncommon, so keep your fingers crossed. It may drop a Pumpkin Treat Basket, which can be found in the Special tab of your inventory, and opened for some goodies! Pumpkin Treat Baskets are also available as free gifts from friends.
You need an additional 20 mice tricked and 20 mice treated to advance to the next sub-location.
Mice from the Forgotten Mice group are now introduced. Switch to an Arcane trap if you have one; otherwise continue using the trap you were using for the Haunted Manor. Basic colored mice are no longer available, but all other mice types from the previous sub-locations still exist. The Zombot Unipire also seems to be more common here, so don't despair if you haven't managed to catch one in the Haunted Manor.
You need to trick 39 more mice, then catch a Trick Mouse that would be unlocked to fill the last box. You also need to treat 39 more mice, then catch a Treat Mouse that would be unlocked to fill the last box.
Trick and Treat mice are only attracted to the correct event cheese.
Once you've filled both bars, the Gourdborg would be unlocked. Catch it using either event cheese to get the Evil Pumpkin Seed! Once you've caught it, your progress is reset and you start from the Corn Field Maze again.
Once you have the Evil Pumpkin Seed you can buy the Pumpkin Pummeler Blueprints (168,000 gold) from the Haunted Terrortories General Store, and craft:
The Pumpkin Pummeler is a Shadow weapon. It's better than the Portals, but not much else. However, it can be upgraded to a much better trap.
To upgrade it you'll need to:
Smash your Pumpkin Pummeler to get 1 Smashed Pumpkin
Get 1 Dragon Ember as loot from Dracano
Buy 24 Tiny Platinum Bars from the Training Grounds General Store
Buy and smash a Venus Mouse Trap to get 1 Venus Mouse Trap Husk
Buy and smash an Obelisk of Slumber to get 1 Obelisk Parts
Buy and smash a Digby Drillbot to get 1 Digby Drillbot Parts
You need 29 million points to craft the trap.
Combine all the items to get the Cackle Lantern!
You'll want to buy new traps to smash into the parts required for this trap; do not sacrifice existing traps that you may want to use!
Note that this is a very expensive upgrade. Between all the smashed trap parts and the Platinum Bars it'll set you back 2,460,340 gold.
You'll be able to upgrade the Pumpkin Pummeler even after the event ends; just make sure you have the Pumpkin Pummeler, as the blueprints are only available for a limited time!
However, this is just a little less than the Clockapult of Time. This trap is a comparable substitute for the Clockapult of Time, with the added advantage of increasing Fire Salt drops in the Jungle of Dread! The only significant disadvantage is the higher point requirement.
On the end of November 1st the event ends. The Haunted Terrortories is replaced with an Empty Event Lot, with no more event mice or items. Free gifts are still available, but the Pumpkin Treat Basket is no longer available.