[Always willing to help. Mystery twins? MYSTERY TWINS. Instead, she pokes his face with the doll's arms and does her ventriloquist thing. Without actually sticking her hand in the doll]

[She's doing that voice]

Don't be like that, Dipper! I just want to be your friend...... FOREVER! Play with me!!

[Then she puts it down, as she's likely gotten the reaction she wanted out of him] Psssht, even if that did happen, at least it'd have lots of doll friends to hang out with. If that's even what this dumb ol' riddle's about in the first place.