ToME: the Tales of Maj'Eyal

how does this work? is every monster i've killed gonna pop up in front of me and strike me down? should i use it?

Every unique that you've killed will all of a sudden come alive again, with the possible exception of dungeon guardians. I found that out by reading it after I killed 90% of them.

There are a couple of uses for this seemingly useless scroll:

• Getting another shot at retrieving a desirable corpse. (Posessors will know all about this.)
• Getting even more artifacts. Let's face it, by the time you can kill off almost all of the uniques, you're probably powerful enough to do it again without too much trouble.

I am not sure, but I could have sworn that I read somewhere that some folks use it for another (4) shots at the one ring, thereby avoiding a grueling dive into angband. If this is the case, dungeon guardians would have to come back as well. I have the thing sitting in a house in case the necromancer does not drop it, so, assuming he does not and I survive, I will post whether or not it does indeed bring those back to life as well.

My recall is that this does not work as a way to get extra chances at the ring, but I've been playing tome4 for a while, so my memory could be slipping.