What makes these new pets special is that they're seasonal wild pets. You can only capture them during Hallow's End, and they require an item to spawn.
To collect these pets, you'll need to gather up 5 Spooky Supplies by completing the four daily quests available in your garrison. These quests are straight forward and pretty easy. Props to the developers for placing the quest objectives all in a centralized area. Less travel time means less time wasted! :)
After you've collected enough currency, speak with Izzy Hollyfizzle in your garrison. Buy Creepy Crawlers from her, and then use the item.
Similar to the Sumprush Rodent's Rodent Crate, the item will spawn a bunch of wild pets in your garrison.
Unlike the Rodent Crate, the wild pets do not despawn! They persist through logging out and zoning, and I'm fairly confident they will last throughout the entire in-game holiday since they're supposed to be "spooky decorations". We'll see though.
You can invite others to your garrison if they want to collect the wild pets. The pets are targetable by player spells and thankfully, are insta-respawn if you come across a breed or quality that you're not interested in. Makes for quick searching if you just want to find a rare or specific breed.
These pets also count as standard pet battles, so you can farm pet experience from within the comfort of your (or someone else's) garrison. :D
Each pet comes in 4 or 5 breeds, so I had trouble deciding which to keep and which to release. Normally I wouldn't be concerned about wild pet breeds, but since these pets are exclusive to this event, I'd rather not miss out on a breed and then have to wait an entire year to collect it.
Thanks to Lio and Jere, I settled on the following breeds:
Ghastly RatI haven't noticed any of these pets doing anything interesting for their idle animations, which is a shame. Maybe I just haven't idled long enough though? *crosses fingers* For pets that re-use existing models, it would be awesome if they had an interaction. Something new to add to something old(er), yenno? ;P
Ah well, I'm really satisfied with how collecting these new wild pets turned out. Since this new mechanic worked out well, does this mean future holiday updates could include seasonal wild pets too? I'm half hoping the answer is yes! ^_^