I don't have the biggest amount of data to create a case regarding how they work but here's some stuff that happened to me concerning monster cards, in chronological order: - A few hours before the server reset I got a Shark card and a Jar card - Upon picking up they stayed on my inventory as a "Use item", going to the NPC on NLC did nothing - Post reset I get a cooleiezombie card, this time it registers, gives me a message it registered on the book and it didn't stayed on my inventory as a use item - Thinking that the effects of the cards became active post-reset I dropped my cards as they were cluttering my inv - I get another card, this time it's a Jr. Pepe one, but once again it gets added on my inventory rather than registering it on the NLC book (no message and sound effect), although this time I notice what's possibly causing it is that my pet picked it up. I don't really remember if I directly picked up the coolie zombie card but it does feel like I did when I think about it Not a very helpful statement but I wasn't really thinking about it when I did wew If anyone had a similar experience or a different experience it would be nice of you if you could share it, I only came across 4 cards so it doesn't really seem enough to create a conclusion Spoiler: monsters cards pics
Got a yeti claw machine card and picked it up with the character and it registered on the book my pet got a pepe claw machine card and it's on my inventory so at least on my case it seems that it doesn't register if my pet picks up the card