Donna and Mary Lila Grace Thibodeau are a pair of sisters in Carrie (Novel)
They are members of The Mortimer Snerds
Donna and Mary Lila Grace Thibodeau first appear in the locker room where Carrie White gets her period and begin to taunt her by yelling "Plug it Up!". Both of them get detention from Miss Desjardin. Both of them attend the prom and Donna is collecting the tickets when she notices Carrie and her date, Tommy. When Chris and her boyfriend Billy Nolan dump pig's blood on Carrie, Mary and Donna both burst out into laughter along with the rest of the students. When Carrie takes reveng on the school with her telekinetic powers, Mary and Donna are presumably electrocuted or burned alive during the mayhem.
Donna and Mary are referred to as "the twins" but it is unknown if Donna and Mary are identical or fraternal twins.