[Hedgehog Fog]

EFFx
If you talking about npc preset, it's just a basics setups for npc (private data) like movetype, solidtype, takedamage etc.
If you wanna make something like npc, you need to add hook for think, make first think in spawn event for entity and set pev_nextthink every think event.
In think event you need make some npc logic, like target finding and attack.