Lua scripts are run when the lump or wad is loaded, and besides actions that it performs when it is first run, it creates functions which are code you wrote in Lua to be run at certain times, and hooks for triggering and sending information to those functions, such as replacing a mobj's thinker, running at map load, running when a mobj takes damage, running when triggered by a linedef executor, etc.EDIT: Which reminds me. Is Lua tied to the map (e.g. executed with a linedef executor) or autorun on load or what? As in, how does a Lua script get activated?