The Tavern

I sometimes like playing as a Spriggan enchanter and i was thinking it would be nice to have a "mass sleep" type of hex spell in my arsenal. In the late game you have Discord, which is a good hex spell, but perhaps a mass sleep spell could be good for the mid game hex spell. You do have "Alistair's Intoxication" for mass confusion, but it's a poison / transmutation spell. If you could make a all the monster in your view sleep, you could easier escape or stab multiple enemies before they eventually wake up. I don't find "Dazzling flash" very helpful, so you perhaps replace that one for a new spell.

As a side note, it would be nice if there was an indication that the monster was about to wake up. Perhaps they could snore if in deep sleep

Such a spell would be incredibly OP. I'd suggest using silence + attraction potion as a combo for stabbing many sleeping enemies. As far as enemy sleeping goes I suggest checking hellmonk's stealth megapost in the dungeon crawling advice section of this forum. There is o such thing as deep sleep or monsters being about to wake up.

What kind of situation would you use this for? I don't usually find many ?silence or !attraction, but I find many many rooms full of sleeping enemies.
What groups of sleeping enemies do you save your consumables for?

I recently used it in Elf 3 to stab the majority of the enemies in the end vault. Another time I stabbed all but 1 monster in Tomb 3 with that combo! You can use the silence spell instead of attraction too. Where you use it depends very much on the char, just like other consumables.