"Other Mommy" - Don't Tell Mom the Babysitter's Red

Bella (Arabella Olivia Clark) senses something wrong with parents (Jessica Chastain and Jay Duplass), but that's alright: she has another mother who looks exactly the same, living inside of her cupboard...

(Credit: Bloody Disgusting)
Arabella Olivia Clark is remarkably good, and the movie begins a fascinating premise as it follows a child aware that things are wrong and awry, and unable to trust the ones she loves. It lends itself well to paranoia and themes of grooming and how we treat and believe children. It has some spooky, odd monster design and a rather unusual pace and structure, it's twisty and odd and a little silly but with dedicated performances.
After 45 minutes you can switch it off, as the moment they hit Grandmas's (Karen Allen) house it nosedives and shits the bed entirely. What was funny and odd and promising turns into a drudg and a slog as it threatens to embrace the silliness by crossing over with the "Insidious" universe, and features Dichen Lachman whom I like, but become silly and laughable and not intentionally so, losing its momentum and the arcs about family and togetherness.
I can see it becoming a cult campy classic a few years from now, but not for me