“ A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.”
“ After a long night of reveling and merriment celebrating their latest victory, one of the PCs awakens with his/her head shaved and a large ornate tattoo on top of their head. Tacky, yes but also a painstaking work of art that has left them with a headache to beat their hangover. The kicker? It is a huge symbol of the god of Evil, Assassins, the Drow, Munchkins, something really really offensive”
“ 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.”