Lam's Mod Master is an add-on that allows you to add your own custom attributes to mobs, NPC, and other player-created items in the world. It can be used for various purposes, such as for an in-game telephone to talk to other players, to mark an NPC or mob as a friend or an enemy, to create an in-game diary, to help an NPC learn new skills, and so on. It can also be used to create custom items, custom mobs, and custom maps. It is a very versatile add-on, which means that you can use it to create all kinds of things.