The Cat Who Walks Through Walls
When was the last time you saw a cat quantum tunnel its way across a wall (barrier)?
Can't say as I've ever seen it happen with my own eyes, but the indirect evidence is compelling: Cats are always showing up where they have no business being and with no reasonable way to have gotten there. When you encounter the mystery of the murder in a locked room, the correct answer is "the cat did it".
"When you've eliminated the impossible, whatever is left, however improbable, must be the truth." So sayeth Sherlock Holmes.