Question: what exactly are chucklevoodoos?

They’re Psychic Powers Purples have that induce Nightmares on those around them. Through binding the Purple Caste to Lord English’ cult, they pretty much ensure his influence reaches every aspect of Troll Society, Sopor Slime being the only thing that can keep these violent Nightmares at bay. Fear tactics, messing with one’s mind… It seems that prolonged exposure to these can lead to full on mind-control like with Meulin, making it seem like a sort of telepathic corruption thing. Gamzee uses this power to inflict Nightmares to materialize both Cal in Dave’s Bedroom, and the Jack doll in John’s Bedroom in their Moons, making him responsible for both Lil Cal’s ‘origin’ and Jack’s eventual Ascension. Suck on THAT Vriska.