Can't remember the name of the phenomena.

The one that results in the world being inverted when viewed through a convex lens.

Yesterday it was 'Avengers', today it was 'The Cabin in the Woods'. Name a genre of movie, sci-fi, cult, slasher, apocalyptic. There is an element of each in there somewhere, and no I did not guess the end, and neither did my friend C1. Horrible, silly, nasty, hilarious, and considering every single cliche had been used till threadbare in other movies very original .

Loved it.