A Trailer for the Exorcism Flick "The Devil Inside" Accidentally Played to Families Waiting to See "Puss In Boots"

Some British families were settling into a U.K. theater to take in a screening of the "Shrek" spin-off "Puss in Boots" . . . when their eyes were assaulted by the trailers for the exorcism film "The Devil Inside" and the "Ghost Rider" sequel.

Obviously, the kids freaked out and their parents weren't happy.

One father said his daughter was, quote, "extremely frightened by what were exceptionally strong images, even by adult standards . . . I tried to cover her eyes."

And a mom said, quote, "It was every parent's nightmare . . . kids watching exorcism trailers."

The theater manager said the trailers were meant for a different movie, "Underworld Awakening". He doesn't know how they ended up in front of "Puss in Boots".