Here's a list of 50 quest hooks involving creatures from both the Monster Manual and from the content I created during Shapeshifter Week. New creatures have links to the posts that contain their statistics. Existing Monsters can all either change their shape naturally, cast polymorph, or cast disguise self.
| 01-02 | A group of Doppelgangers are getting into trouble all over the city. Everyone wrongly blames the local paladin hero who the Doppelgangers have taken the form of.
| 03-04 | A Therianthrope is capturing and replacing the creatures in a certain city district with younger Therianthropes.
| 05-06 | A covey of Green Hags disguised as three humans have started a bookstore and is selling books that trap their readers in their stories.
| 07-08 | A Doppelganger has taken the place of a town's wizard even though it can't cast spells. Now it has to cleverly imitate the spells that the locals pay for.
| 09-10 | An Oni has taken the form of an innkeeper and is devouring the guests it deems the most "appetizing."
| 11-12 | A Hagunemnon has appeared in a populated city and is massacring citizens like a wildfire. Everyone is in a panic but no one can determine the cause thanks to its ability to shapeshift.
| 13-14 | A Tula Hag's mud creatures, in the shape of parents whose souls she has trapped, are going back to town and bringing their children to her river.
| 15-16 | A kraken is demanding worship from a cliff-side village of Kuo-Toa. The kraken is actually a Doppel-Gang that lives in a cave at the base of the cliff.
| 17-18 | A Monopod has accidentally gotten itself into a situation where a dwarven kingdom thinks it's their lost king. Now it is having the dwarves raid for treasure which it hoards in its new "home."
| 19-20 | Children have started playing relentless pranks throughout a village. When questioned, they all say they got the idea from a talking animal; really a Puca in disguise.
| 21-22 | A Doppelganger has fallen in love with a humanoid and keeps taking new forms in hopes of wooing them, but keeps getting rejected.
| 23-24 | A dwarven guide offers to guide the party through a complex cave system. In truth, it's a Monopod that is leading them to a trap to steal their loot once they are dead.
| 25-26 | A Bouda is posing as a blacksmith in a small village. The items it makes are cursed.
| 27-28 | A damsel in distress is rescued. However, she has been replaced by a Succubus that wishes to take advantage of the damsel's wealthy noble husband.
| 29-30 | A hunter has offered the PCs the chance to hunt a powerful monster in return for gold. In truth, the hunter is a Weretiger that wishes to hunt them.
| 31-32 | A Sea Hag pretends to be a woman trapped on a desert island, flagging down passing ships and offering them a tropical banquet laced with Midnight Tears.
| 33-34 | A Swarm Shifter is "bugging" the offices of diplomats, and is blackmailing them using the information it has gathered.
| 35-36 | A magic item's blueprint calls for a certain type of flower. It turns out that the flower described is actually a Blodeuwedd that knows the secrets of the item's creation.
| 37-38 | A Doppelganger is using its talents to lift heavy pockets and get away clean.
| 39-40 | A Phasm has killed all the monsters in a dungeon in order to pretend to be all of the monsters by itself. As heroes "slay" one monster, it retreats in the form of a ghost only to impersonate the next monster that would have been in the next room.
| 41-42 | A Quasit has decided to convince young women that he is a prince disguised as a toad, and they need only to kiss him to return him to his true form.
| 43-44 | A Werebear has snuck into the ranks of a military encampment in the forest. Angry at the newcomers in its territory, it is picking off the soldiers one by one.
| 45-46 | Creatures travelling a certain road report strange surreal sightings or experiences. A Puca is to blame.
| 47-48 | A Green Slaad disguised as a dwarf mage is looking for the control gem of a Gray Slaad who hid it within a lost dwarven mine. It intends to use the gem to force the Gray Slaad to reveal its secrets of ascension.
| 49-50 | A Deva has taken the guise of a street urchin to investigate an evil cult growing in a city.
| 51-52 | A Couatl senses its impending death and seeks out another Couatl to mate with in a dangerous land. Disguised as an elven druid, it looks for heroes to help find another Couatl.
| 53-54 | An Incubus has seduced a member of the royal family and is now convincing their partner to introduce unfair laws and taxes on their people.
| 55-56 | A popular gladiator in a tusked helm is actually a Wereboar intent on spreading its curse to other pit fighters.
| 57-58 | Leshies warring over territory have led to each taking on disguises and recruiting wandering heroes to slay one another.
| 59-60 | An Aswang's true identity has been discovered by a group of people. Now it's trying to clean up the mess by either erasing the memories of witnesses or killing them, one by one.
| 61-62 | A Mechadaptor Titan has been built to protect a city's vault, but the construct will no longer follow commands.
| 63-64 | A Hamrammyr has found its way near a dragon's lair and is trying to devour more and more powerful creatures until it thinks it can kill the dragon. Powerful monsters' corpses litter the surrounding wilderness.
| 65-66 | A Yochlol has infiltrated a group of drow rebelling against the matriarchy to tries and dismantle the rebellion from within.
| 67-68 | An Aranea seeking a certain magic item has disguised as a noble to task heroes to quest for it, promising wealth it does not possess.
| 69-70 | A Leyak is committing arson throughout a town while trying to frame other creatures for the deed.
| 71-72 | An entire forest is overrun by one gigantic subterranean fungi that is spawning Sporiforms to spread itself elsewhere.
| 73-74 | A Doppelganger has replaced a local hero for the fame and fortune. When a great monster threatens the town, they turn to their "hero," who wants nothing to do with it.
| 75-76 | A Silvermaster has appeared in a palace decked out with plenty of reflective decor for it to move through. Now the palace's attendants are disappearing one by one, seemingly slain by their own weapons.
| 77-78 | A Lamia attends noble banquets disguised as a noble themselves, beguiling the rich into divulging their trade routes and shipments for it to disrupt.
| 79-80 | A mischievous fey disguised as a repairman is replacing people's broken furniture with Mimics.
| 81-82 | A gang of Wererats are recruiting new members by spreading their curse to unwilling civilians.
| 83-84 | Imps in the form of rats are transporting hidden messages to members of a thieves guild throughout a city.
| 85-86 | A Rakshasa is selling demon-possessed magic items while disguised as a merchant.
| 87-88 | A Silver Dragon has taken up residence in a town as a kindly old woman who claims to be a historian. Their horde of artifacts is left proudly on display, with surprisingly low security.
| 89-90 | A Vampire has risen from a church's catacombs thanks to an ancient curse. A strange mist or swarm of bats can be seen leaving the church each night at dusk and returning before each dawn.
| 91-92 | A Mimic ate a moneylender and spawned in their office. A stack of papers is a horde of Mimic Larvae.
| 93-94 | An Ultraloth has taken the guise of a guild leader for a monster hunting company. It's tasking heroes to bring back living monsters which it then sells to evil buyers.
| 95-96 | A farmer's wife was cursed with Werewolf lycanthropy. She tries to keep up her normal life but she awakens each morning next to dead livestock. It's only a matter of time before she turns on her family.
| 97-98 | An ambassador has been replaced by a Doppelganger to incite war.
| 99-00 | A strange outhouse keeps appearing for those that need it. In reality, it is a Mimic stalking its prey.
