Finally, after waiting a few boots, the missing Halloween event 2024 monster number 4 popped up. I photographed it and although it was about 300k monster, I survived long enough in the battle with it so that I got it tagged for the kill. Then I just went idle and waited for some party to kill it.

The photo album for the event:

la album
This book is mostly a large binder with a rigid black cover. There are
thirty-six stiff white pages where photographs can be inserted.
In addition to the usual book syntaxes:
  album insert <photograph> in page <number>
  album remove photograph from page <number>
You cannot insert a photograph you didn't take yourself.
Removed photos are set to owned.
The label can be set with 'label' command.
This item is in good condition.
The photo album is closed.
The album has all 25 The Hunt Is On pictures!
It looks light weight.

The case (pcity item) for the event:

la case
This piece of furniture is partly a low oak cabinet with a marble top, part
tall glass aquarium-like section subdivided by four glass shelves. It's a
display case, meant to hold and protect trophies from rare and exotic prey.
Syntax: display <item you're carrying>
Only trophies from The Hunt Is On 2024 Event can be displayed.
You must own both the trophy and the bolted case.
        admire <this>
Reflect on your successful Hunts. Get a stat boost until
you quit or reboot based on the number of trophies.
The case can also be bolted/unbolted like a merchant bench.
The label can be set with 'label' command.
This item is in excellent condition.
1:small deer-like antlers of the wolpertinger
2:wet green seaweed strand of the kelpie
3:ragged leather skirt made from lamb skins
4:large bull-like horn of the Cretian minotaur
5:severed head of Medusa
6:black tufted tail of the wampus cat
7:brown furry severed leg of Bigfoot
8:pug-like upturned nose of the hog bear
9:soft-serve ice cream cone
10:giant bat fang of Camaazotz
11:green severed toe of the duende
12:long spine spike of the chupacabra
13:handful of sharp reptilian fangs of hombre caiman
14:glowing scale of Yucamama
15:feathers and turquoise necklace of Xolotl
16:thick grass beard of the eloko
17:twisted paired antlers of the adaba
18:glowing stinger of the adze
19:thick jagged scale of the gbahali
20:giant golden reptilian eye of Apep
21:soaking wet shroud of the anchutka
22:horned, fanged demon mask of the hannya
23:broken bronze fang of the foo dog
24:large brilliant feather of the aspid
25:thick tooth of the Mongolian Death Worm
It looks very very heavy.

My secondary is completely missing all the photographs and kills. But it is a mini riftwalker now, so getting the photographs and kills once more with it feels too laborious.