So I have this idea for a magic weapon which is kind of silly and needs some work, but I think it could be a fun gimmick.
The weapon is a discus (probably uses the chakram's stats (but is a nonlethal weapon) which when thrown imposes a -10 penalty or something similarly difficult to hit a creature with. Upon missing, the discus continues to sail into the sky with no sign of stopping, and the PC's watch as it flies out of view. Then, maybe many sessions later, at a point when s!%& is going really bad for players (such as a pc death or TPK) the discus returns, unerringly striking down a single creature for a decent amount of nonlethal damage and stunning a creature upon a successful save or knocking it unconscious if the creature does not save. The players probably have to be outside fighting a creature for this to work, it would be exceedingly silly for this item to be able to navigate through the halls of a dungeon to strike a creature... though I don't completely hate the idea of that happening.
I'm thinking the trigger mechanism for the discus returning is any time a player character goes unconscious the DM can roll a percentile die with a 10% success rate OR this can simply be the DM's decision.
The spells used to create the discus are probably some combination of spells like true strike, magic missile, and miracle with a particularly high caster level.
It needs work, but I feel that it could be fun to give players a get out of jail free card. It wouldn't be particularly reliable, and identifying it's exact properties should be pretty difficult, to avoid players thinking they could waltz in and take on the big bad because this discus is going to come in and save them. But, I want to know what you guys think! What should the exact statistics on this item look like? What should the save be to avoid going unconscious? Should I nerf its abilities a little?