Ill-Advised D&D Party Concept
Okay, okay, okay. How's this for a D&D party? Sadly, I think this only works in AD&D - later editions smoothed out some of the loopholes I'm exploiting.
Let's say there's an adventurer, we'll call him Bob. Bob goes on a quest in the Underdeep, the massive cavern system filled with monsters and quests beneath the surface of the world. While on this quest, Bob goes into the Plane of Mirrors. A quirk of the Plane of Mirrors is that when a mortal soul enters it, the plane creates a mirror doppelganger of that person - this mirror doppelganger has the opposite alignment, opposite handedness, and so forth of the original. It feels an overwhelming urge to kill its originator and take their place.
Deep down in the Underdeep, Bob's Mirror Doppelganger finds him and successfully kills him! Gleefully looting Bob's corpse, Mirror-Bob puts on a cursed Helm of Opposite Alignment that was in Bob's Backpack. Mirror-Bob is now the same alignment as Bob. Mirror-Bob feels honor bound to complete Bob's quest.
Meanwhile, Bob is so shocked, SHOCKED, at being killed, that his strong emotions make a ghost. So now there's Mirror-Bob, and Ghost-Bob. Ghost-Bob's unfinished business is his quest! He must complete the quest!
Let's pull back a bit. Bob's Mom is a really powerful wizard, and like all really powerful wizards, she can't be arsed to go on quests. UNLIKE most wizards, she cares if the adventurers (well, one adventurer, Bob, her son) she sent on her quest die or not. So, she takes a bit of Bob's hair and nails and she casts the spell Clone, which acts like a sort of save point in this edition (later editions ruin the fun. Fie on them). The Clone will have all Bob's memories and experiences up until the point that the spell was cast and the clone grown. When Bob dies, Clone Bob awakens! Bob had been adventuring for a few weeks or months at this point, so we can safely call Clone Bob a different person than the fella I think we need to call Bob Prime at this point. This is important. Clone Bob hurries out to join his companions to complete his quest!
Meanwhile, back in the Underdeep, Bob's party finds his murdered remains. Rather than cart a body around, they take Bob's pinky toe, and later, in a safe place, plan to have the party Druid cast Reincarnate. This one *might* not be kosher for what I'm doing, so we'll come back to this.
In the Underdeep, there is a kind of floating fungal creature called a Sapromneme. They look like a pale white mushroom cap that's 3 feet in diameter, with about twenty 5-6 foot long tendrils dangling from the bottom of the cap. They only reproduce when slain, where millions of spores explode from their slain form, and waft through the air currents of the Underdeep. When a spore falls on a decaying corpse, it begins to grow and develop into a new Sapromneme. A weird thing happens when a Sapromneme lands on the corpse of an sapient being. It begins to absorb the memories and experiences of that being as it develops. When it's digested the whole corpse and is fully grown, it has essentially uploaded that individual. Sometimes the Sapromneme thinks they're the same person, and have been cursed or reincarnated into this weird alien body. Other times, they realize they're just imprinted with all the thoughts and memories of a dead person, and revere them as an ancestor. Either way, Sapromneme-Bob has a quest to complete!
Okay, there's arguments to be made, and D&D isn't super consistent on this, that a ghost is just the imprint of the emotions and needs of a dead person made on the Ethereal Plane, and the soul is gone off to the afterlife while the ghost mucks about in this world. I'm operating on this model for my fun. So, the party druid has Bob's pinky toe on ice, but it's a hectic few weeks in the Underdeep. There's Drow cities to escape and Svirfneblin to win the trust of. ANYWAY, the druid finally gets the chance to cast Reincarnate - and brings Bob Prime back to life... in the body of a Badger!
Just as Badger-Bob wanders in from off-screen (wandering in from off-screen is canonically how the reincarnated form rejoins the party in AD&D, for reals), Mirror-Bob, Ghost-Bob, Clone-Bob, and Sapromneme-Bob ALSO finally track down their erstwhile companions!
And that's my idea - a party of all Bob!