I headcanon the menagerie pens as something like a pokeball, with room for 20 instead of 1. Also it’s a legit, comfortable pocket dimension, instead of straight digitizing your animals.
The shape is literal and not metaphorical, it’s a little pendant charm, maybe the size of your palm(or a…tamagotchi…). You can look inside to see your pets wandering around in there.
Also you can store your stuff in them, which explains the immense piles of junk you can carry on your person at any moment,
I am undecided on whether or not worldhoppers can enter them, too. With a name like worldhopper it makes sense that they could, but I like the idea of them only being able to put things in & take them out. (Maybe they CAN enter, but only if they’re not carrying any other charms. Don’t put a pocket dimension in a pocket dimension it doesn’t end well.
Personally my worldhopper carries all of their habitats on a keychain, it’s very jingly
