Gravity Falls (2012)

S1E4 The Hand That Rocks the Mabel

Dipper and Mabel find themselves intrigued by their charming new neighbor, Lil' Gideon, who is secretly the beloved psychic of the town. However, when Gideon pressures Mabel into a relationship, both siblings quickly realize that his endearing facade can disappear just as swiftly as it appeared.