I absolutely support the idea of ​​it being a Backpack (with Textures in the game), something that can be found or made with materials, such as combining pebbles, vulture masks and fabrics (perhaps pole plant vines, lizard skin and centipede legs, ex. when you kill any of these creatures it can be collected if you have a spear near the body by holding shift), made in different sizes and purposes (to hold 2~3 small items like pearls, pebbles, bombs, neurons or food and a dedicated backpack that can't hold small items but allows any slug to carry an additional spear), scavengers could have a small chance to spawn with backpacks too, just a few thoughts, this is something I really wish was in the main game.