[While he's being Dipper about it, Mabel picks up the creepy doll]

This is some authentic horror movie stuff! Right, Dipper?

[Then she uses the doll's hand to poke him in the cheek...... the mystery twins are back in action alright. Complete with Mabel being Mabel about it while he's overanalyzing the riddle...... well, fine, she'll contribute a little:]

There's nothing around here really to take. Except for this creepy guy!

[They're probably doomed]