[ChibiChibiLuc]

object.catchevent(name,event,newevent);

It calls 'newevent' every time 'event' is called.
It's main use is in GUI Controls, when you use a for() to create multiple buttons. You can use a catchevent to make clicking each button call the same event.

npc.catchevent(#N,"onPlayerEnters","onCreated");
This calls 'onCreated' each time 'onPlayerEnters' is called.

By the way, I only think npc. is required when it's used in an NPC Weapon. I don't know for sure, as I haven't tried it without the npc. prefix.