As food goes, the humble cucumber is pretty innocuous. It's 95 per cent water and 100 grams of it will set you back just 16 calories.
It also is an inanimate object. Yet cats are utterly terrified of them.
No one really knows why, but the reaction of felines when one is placed quietly behind them, is one of the funniest things you'll ever see.
A new compilation has been created by Youtuber MrFunnyMals, showing a host of fantastic reactions to the evil cucumber.
Speaking to The Telegraph, animal behavioural specialist Dr Roger Mugford speculated: "I think that the reaction is due to the novelty and unexpectedness of finding an unusual object secretly placed whilst their heads were down in the food bowl. Cats have to be suspicious of the unknown: it could represent the danger of a snake or another predator. I suspect that there would be the same reaction to a model spider, a plastic fish or a human face mask. So not an inherent feature of cucumbers, just their unusual context."
Still, it does always seem to be cucumbers.
Watch the compilation above - and also possibly our favourite below.