When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.
Other improvisational weapons/tools:
Icicles are useful as daggers,
Bag Of Holding filled with copper pieces used by chucking the contents at foes, (by strolen)
sleeves make useful garrotes. Ya can't cut anyone's neck, but you sure can choke 'em!
Flaming Logs make great clubs, (any Barbarians out there?)
and Bee hives are very effective when thrown at a mob of enemies. :-)
Perhaps divinations, if strong enough, can actually change the future, instead of predicting it.
You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)