I have created a mod for a pc which he meet's other npc's that i have created in a certain place.

I was woundering if there is some other line of code i could include into the script of the npc, so that when i go through that area a second time that the npc is not there.

Also can i get a good example of an "on enter" script.
Say i wanted to spawn an npc named ABC when i enter a certain module how do i do this.
And when i go through the second time around he is not there.

Thanks for listening
n1gamer