Bananas.

Even when you're not on Twitter or Facebook, the pop-ups memes will find you. This one was particularly intriguing, I had to admit:

Now, obviously it is a mean practical joke to convey terrifying messages to strangers by the use of common produce. I had to wonder two things right away: 1) What kind of a monster would do such a thing? And 2) Could it really work?

Well, you can read about the results of others, but for my money there is no substitute for experimentation. I'm sciencey like that, you know. So on the weekly trip for sustenance, I got some bananas at the supermarket, including this fine, almost-ripe specimen below.

I wanted to try to replicate the furtive scratching one would have to do to pull off this prank. I decided that one would probably want to do the scratching with a fingernail, because if you were going to put the message on a banana while in the supermarket, you oughtn't draw attention to yourself by messing around with a paring knife. However, if this plot was to work, the initial writing had to be nearly invisible -- so I decided to scratch my message using a common sewing needle. The flaws in the plan began to appear long before the writing did.

First, it's tricky to scratch a message on a banana without actually breaking the skin, which would make it an unappealing (ha!) banana and one less likely to be bought. Second, you see that the writing was immediately visible despite the thinness of the needle; the second picture was taken a minute after the first, at 10:44 a.m., when I should have been working.

I put the banana aside and went about my business. By 4:08 p.m., the message had emerged:

The writing came through beautifully. But now we see the other problems:

1) When writing furtively with a needle in poor visibility, it's hard to see what you're doing, and easy to forget even the D in Fred.

2) This vivid writing was seen little more than five hours after it was made. Unless the bananas were flying out the of store that day, it is unlikely that someone would buy the fruit and get it home before the writing appeared. I don't even know when it did appear, as I wasn't checking it. I didn't expect to see the writing that quickly. It might have been visible by noon.

So maybe planting the etched banana in the store for a future customer wouldn't work. I thought, suppose you etch the banana and slip it into your kid's lunch so your embarrassing message would be visible when he opened the bag. Something humiliating: Mommy loves baby kiss kiss. That'll teach him to "forget" to mow the lawn.

But no -- the key to the joke is that the writing appears while the banana is untouched. So unless your kid inspects his lunch before he leaves the house, you might as well have just written on the fruit with a Sharpie. He'll know you wrote the message, roll his eyes, and complain to his friends.

So there you have it -- as practical jokes go, this one has a low probability of succeeding.

But now I'm thinking about the possibility of injecting hot sauce into avocados....