Buildings and spells

I must be missing something very stupid, but is it possible for computer controlled buildings to cast the spells on their ability set?I am almost certain it is, there is the forgotten one from the sp campaign taht keeps summoning tentacles and crap, and I have this big bad building who won't cast any of its big bad spells for some reason.

Is it triggered? I don't think you can normally do this... unless it's an arrow/orb based spell...

I want to avoid triggering for a task that would be performed better by the game's AI.

You can run one of the AI scripts via triggers and the units will use many of the default Blizzard abilities, although I've never played with this myself.

If you have weird custom spells or whatnot, of course you may have some additional difficulties that require custom AI scripting via triggers.