Holiday Pet Hats are rare seasonal accessory items in Creativerse that can occasionally be found solely during the annual Christmas event that lasts for ca. one month.
These accessories cannot be crafted, just like common Pet Hats, and they also do not stack, so that each of them requires one slot in storage, even though these accessories do not have a durability bar.
Holiday Pet Hats were introduced for the first time with update R26, the "Holiday Surprise" event, on December 14th 2015.
How to obtain
Holiday Pet Hats were part of randomly spawning Holiday Gift boxes during the first Christmas-event "Holiday Surprise" from December 14th 2015 until January 13th 2016, then again during the Christmas-event "Haunted Holidays" from December 16th 2016 until January 25th 2017 (that also included a return of the Ghost Creatures from the Halloween-event 2016), and once again during Elfi's Toy Drive from December 13th 2017 until January 10th 2018.
During Elfi's Wonderland from December 19th 2018 until January 25th 2019, they could also be obtained from randomly spawning Holiday Gift-boxes, but additionally to that Reinbeaus were introduced to the game that could be killed and would drop loot bags then that could either contain one Small Trog Trap, or a stack of random Christmas-themed items like Holiday Pet Hats, or 12-14 Rescued Toys.
The very rare fast Reaudolphs additionally appeared during Elfi's Wonderland in cold biomes amongst Reinbeaus and would drop special loot bags that could not only contain Holiday Pet Hats and other Christmas-themed items, but also rarely 100-200 Rescued Toys at a time (but at other times no Toys at all) when killed.
During the Christmas event 2018-2019, neither Reinbeaus nor Reaudolphs could be tamed.
Holiday Gifts randomly spawn during Christmas event-times (usually for a month around Christmas) on blocks of Snow and Ice all over the surface during (ingame) day and night in a certain proximity around player characters.
Holiday Pet Hats cannot be found in common randomly spawning Treasure Chests like other types of Hats for your Pets, and these accessories cannot be crafted either. Different from most Christmas-themed items, these Pet Hats also cannot be bought from Elfis (NPC traders that spawn during Christmas-events), and they even were not part of any Store-exclusive Christmas-themed Recipe Packs or Item Packs (neither Elfi's Toy Drive Bundle 2017, nor Elfi's Wonderland Bundle 2018, nor any of the 3 Make-A-Wish Community Reward Bundles or 4 Make-a-Wish Donation Bundles).
Even though several Trog Trap Event Creatures can wear Holiday Pet Hats, these will not drop after killing them, and Holiday Pet Hats also do not seem to be part of any randomly provided Holiday Gift reward box for successfully completed Trog Trap Events.
If you tame a tameable Trog Trap Event Creature like Ice Spies, Target Arctic Mirus or Miru Minions, then these Creatures will appear as if they wore a Holiday Pet Hat (in case of Troggington's Minions, these Hats aren't red, but blue), but they do not feature any actual Hats in their hat slots in their Pet Windows.
If you dress these Trog Trap Event Pets with any actual Pet Hat accessory (by placing such a Hat into the hat slot of their Pet window), then the original Pet Hat they wore will be replaced and not return if you remove the Pet Hat from the hat slot in their Pet window.
How to use
To dress up a Pet of yours (or Pets of other players that you are allowed to access), open the Pet window by using right-click or "f" (as the default key) while looking at the Pet, then click on any accessory that you have found, like the Holiday Pet Hat, and that you are currently carrying in your inventory (these non-placeable items can't be put into the quickbar) in order to automatically move it into the correct accessory slot of the Pet.
Alternatively, you can drag the accessory from your inventory to the Pet window with the left mouse-button and drop it over the correlating Pet accessory slot.
Player characters can wear similar Holiday Hats too, but not the ones that have been "made" for Pets - instead, a special player Holiday Hat can be bought as a Costume in the Store for Coins (that can be bought in the Store in the shape of Coin Bundles for real money via Steam Wallet).
Playful has warned players that seasonal hat Costumes like the Holiday Hat for player characters might only appear in the Store during Christmas event-times in the future.