Maybe cucumbers resemble some dangerous adversary in the alien world cats originally came from. I have to do some grocery shopping today, and I think I'll buy a cucumber...

Cats are both predators and prey. When eating, sleeping, urinating or defecating, they are at their most vulnerable. Something that large that is not afraid of them is something to be concerned about when it appears behind them suddenly, with no warning at all. C

Cats survive in nature by being hyper alert, and by eating only in safe circumstances, not in circumstances in which a dangerous creature could sneak up on them.

Their trust has been badly violated. Now some of them will probably feel antsy and nervous while eating, especially if their humans do this sort of thing repeatedly while the cats are doing things they would normally think they are safe doing.

you never get a warning

those peacefully sleeping cucumbers that hadn't snuck up behind them. One cat started beating on a cucumber that was next to some peppers and left the peppers completely alone. I think there's something about cucumbers that cats find disturbing. I've never seen a cat attack a much larger and potentially more dangerous vegetable, like a pumpkin, except maybe to chew on it.

Okay, that's a good point . . . But it is still pretty hilarious. I used to have a cat a couple times in my adult life, and they do freak out pretty good when startled, which I didn't do on purpose, and it cracked me up. So I dont think its really cucumbers, you could sneak a teddy bear there behind them and they would react the same I'm sure.

One of them sniffed it briefly. The others ignored it. Maybe it was the wrong kind of cucumber.