VRChat has 1000 id's (per user) it assigns to prefab objects with Object Sync that are dynamically spawned. These id's are not recycled. This means that if you make a gun, that spawns prefab bullets, you can run out of id's within 5 minutes. When this happens, VRChat breaks, you can no longer do any function that relies on assigning an id, you can not even make a portal to go to a new instance.
This is a huge limitation of spawning prefabs, putting a huge hamper on many cool game ideas in worlds.