unique mobs and objects

Can Mobs be reset at different times from the area they are in?
Can Objects also be reset independantly of the area?
Can triggers or traps be used to open doors, or cast spells?

Example:
Create a Mob called Balrog.
Balrog has a magical flaming sword
Clicking a button three rooms away opens a gate/door that releases the Balrog.

The Balrog being a very unique Mob in the game should reasonably only appear say once a week or even once a month in the game. Obviously, there would be other Mobs in the area that would be more frequently. The goblins are the area mobs that guard the room with the button in it to open the gate that maybe summons the balrog (ie casts a spell to summon) or 'releases' the balrog from his 'magical' bonds. The area would reset every 30 minutes, but the flaming sword and the balrog would appear 900 minutes or longer if possible.

If the Balrog is not in an area reset it shouldn't appear when the area resets, and to make it appear I would probably make a goblin (or whatever) have a low probability of creating one. Or, simply build into the server a timer that fires every so often that puts it there.

Easier solution would probly be a mobprog to control the balrog possibly spawning when the button is pressed. Ultra common easily identified mob can be placeholder for the Balrog you want to be the ultra rare spawn. Give the placeholder say 80% probability of spawning when the button is pushed and the Balrog should be quite rare to justify the reward he offers :) Granted, it would be possible to get several Balrog spawns in a row but the odds are quite hellish.

Nick - When you say build a timer into the server I'm not clear what you mean? Can you explain a little more please?

Meerclar - I've never written a Mobprog before. Could you give me an idea on how to do this?

I'm assuming that if it can be done with a Mob then it can be done with Objects as well.

Example:

A magical sword that would only appear on "full moons" or once a month. Is that correct?

The server has provision for timed events (eg. a spell wearing off) - you could add one of those. However if you are not familiar with coding then Meerclar's idea is probably better.

Oprogs as I recall are used to make the obj do something special rather than control when/how they spawn. Code for the mprog would be something similar to:

act P pushes the button (or whatever other action trigger you want here)
prog code:
[code]
if rand 80
mob at <Balrog's Room> mob load mob <placeholder vnum>
else
mob at <Balrog's Room> mob load mob <Balrog's vnum>
mob load obj <Balrog's sword>
mob at <Balrog's room> give balrog <swordname>
[/code]

Granted, I havent tested that code and it may not be the proper commands for smaug mprogs, but, I dont code/build on a SMAUG mud.

Thats the general idea though. stash that prog on a hidden mob in whatever room the trigger for the Balrog's room is in and it should be a beautiful thing.