This is homebrew, submitted by a member of the community.
Cackler
Cackler
Small Fiend (Demon), Chaotic EvilSmall Fiend (Demon), Chaotic Evil
Innate Spellcasting. The cackler’s innate spellcasting ability is Charisma (spell save DC 11, +3 to hit with spell attacks). The cackler can innately cast the following spells, requiring no material components:
At will: Fire bolt
1/day: Tasha’s hideous laughter
Last Laugh. When the cackler dies, it releases a dying laugh that scars the minds of other nearby creatures. Each creature within 10 feet of the cackler must succeed on a DC 11 Wisdom saving throw or take 2 (1d4) psychic damage.
Mimicry. The cackler can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 11 Wisdom (Insight) check.
Innate Spellcasting. The cackler’s innate spellcasting ability is Charisma (spell save DC 11, [+3] to hit with spell attacks). The cackler can innately cast the following spells, requiring no material components:
At will: Fire bolt
1/day: Tasha’s hideous laughter
Last Laugh. When the cackler dies, it releases a dying laugh that scars the minds of other nearby creatures. Each creature within 10 feet of the cackler must succeed on a DC 11 Wisdom saving throw or take 2 ([1d4]) psychic damage.
Mimicry. The cackler can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 11 Wisdom (Insight) check.
Actions
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4+3) piercing damage.
Spiked Chain. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 6 (1d6+3) slashing damage.
Bite. Melee Weapon Attack: [+5] to hit, reach 5 ft., one target. Hit: 5 ([1d4+3]) piercing damage.
Spiked Chain. Melee Weapon Attack: [+5] to hit, reach 10 ft., one target. Hit: 6 ([1d6+3]) slashing damage.
Legendary Actions
Details
Cacklers are small, jabbering jesters that spice up Rakdos performances with their chaotic antics. Their incessant cackling can inspire uncontrollable laughter by making everything—even the most horrifying spectacles—seem hilarious. Some cacklers excel at vocal mimicry and perform as impressionists; others put their sadistic bent to use by lurking in shadows and terrifying passersby. Rakdos performers enjoy dressing cacklers in a variety of masks, hats, and costumes to lampoon public figures. Cacklers are small, jabbering jesters that spice up Rakdos performances with their chaotic antics. Their incessant cackling can inspire uncontrollable laughter by making everything—even the most horrifying spectacles—seem hilarious. Some cacklers excel at vocal mimicry and perform as impressionists; others put their sadistic bent to use by lurking in shadows and terrifying passersby. Rakdos performers enjoy dressing cacklers in a variety of masks, hats, and costumes to lampoon public figures.Shout outs: Stacey, Adam Fowler, Amanda Kettles, Angelo Anderson, Appreciate Witch of Life, AstroLass, bilbens baggo, Brian Nunziato, Bryan Sheairs, Brysen Packer, Bryson Waits, Burlyfighter, Caitlin W., Christopher Allbritton, CJMAXP, Connor, Dalton Elliott, Damon Carrington, Daniel Edwards, David Schraff, Dragons With Jetpacks, Elisa Martinez, eric sun, Ezzela1891, Federica Frezza, Gordon Alexander Fallon, Gundar Wez, Iofire, Irate The Pirate, Jade Arrowood, Jake Lane, Jeremiah Walker, Jess, Joe Dalby, John Nazario, JollyGamer, Jonathan Lekse, Jordan Brazeal, Joshua David Maddox, Justin Snyder, Kerry Melton, Kevin, KFB_Patreon, KingHavok1217, Kingyo Senpai, Kyle Clark, Lisa Tucker, Liz Fontain, Lizzie, Lou Bliss, Luke P, Mario Pizzamiglio, Mark L, Matt Yates, Max Hops, Maxwell Mayer, Michael Hamilton, Millergendraft, mtnman1979@aol.com, Mx Charlie, Mylon Schroder, Nahellion, Nathan, Nicholas Zamora, Nick Soucy, Phil Mehl, Phillip P Torchia, Pythor Sen, R., Rachel Anderson, Ray Bissonnette, Remora Jewel, Robert Rich, Robert Skadsem, Ryan Flagg, SallySparrow132, Sarah Holland, Serafina Moon, Shane Andrews, ShortyMcgibble, Sik Makoyi, Siren, Stefan Gottschalk's, Steve Rosenlund, Stuart, Syn21, That Video Editor Nic, thea musing, Trev909, Vedie V, Vincent Drone, Warren Clarida, Wesley Muncy, XMrMonkyx ., Zachary Burgess-Hicks, zachary gee, Zealot23, Zee Livezey
Their contribution stands as a beacon of hope for all adventurers!

