Robotic Spider Spawn ( Robot sentry )

anyone knows how to spawn a working robot sentry ( these that help you to kill enemies and spot the way?
if you do the common SPAWN command using a sentry, it appears "FOLDED" ( inactive )

I haven't done enough research but you'll have to "trigger" it with a trigger_relay enitity, then have it target its enemies and path enitities.

Or, you could just take a look in one of ID's maps.