Kimmy's villainous mother
Kimmy's unnamed mother (Julie Nathanson) is a villainess from "I Scooby Dooby Doo", episode 1.22 of Be Cool, Scooby Doo! (airdate June 20, 2017). She was the mother of Kimmy, an old friend of the Scooby gang who was planning to get married to Nate. As revealed in the episode's climax, Kimmy and Nate's families hated each other and Kimmy's mother colluded with Nate's mother to ruin their children's wedding and drive them apart.
To commit their plot, the scheming mothers used the local legend of the Ghost of the Cliff Bride, with Nate's mother dressing as the ghost bride and Kimmy's mother directed her as she wrecked havoc on the wedding due to the former's poor eyesight. She additionally used the DJ system to project a hologram of the bride during the wedding, ruining the ceremony and turning Nate and Kimmy against each other (as Kimmy became upset at Nate for hiding the problem from her).
Later on, though, Nate's mother was caught by Daphne, who tackled her and brought a tent down on top of her. After she was unmasked, Kimmy's mother was exposed as her cohort and the women's scheme was brought to the light. But after seeing how their children had fallen in love despite the bad blood between their families and seeing how their ability to work together in the plot showed they weren't so different after all, the women appeared to make peace with one another and watched approvingly as their children were married.