Anti-Mabel

Mabel "Anti-Mabel" Pines is one of the alternate universe versions of Mabel Pines trapped in MAB-3L, the realm where the lost Mabels remain, and the main antagonist of the section "Don't Dimension It" from the Gravity Falls book "Gravity Falls: Lost Legends". She is an evil alternate version (a doppelgänger) of the main Mabel who plans to destroy the latter's realm by pretending to be her friend.