Note: I play 2nd edition, using much of the optional material. However, I have zero issues (I do it frequently) grabbing content from other editions, from other games, or just making it up on the spot.
I am a noob DM, and am currently running my player's through a series of Necromancers. They are under the nation's orders to kill every necromancer in the area. So far it has been going smoothly.
Due to a series of minor victories they have become hot-headed and are going to storm the main necromancer's keep. This necromancer is a demi-god, likely roaming around 16th level. Therefore he needs some cool (aka, flashy) powers that will clearly separate him from his underlings.
I like the spell "Stone Heart", but that isn't too 'flashy' (especially since their party isn't nearly strong enough to survive this encounter without divine intervention, which they will get.
So; I am looking for idea on what showy flashy thing this Necromancer could do to elevate him above 'just a bigger baddy'.