Coin IQ Test Prank

I love this prank. It's great for some laughs and works almost every time. The nature of it also means that no-one is likely to suspect it of being a prank. It works really well with an audience. 

Step 1: What You Need:

- A coin
- A good-natured victim
- OK story-telling skills

Step 2: Setting the Stage

- Wait for the right time, like a gap in the conversation. Then say something along the lines of "hey, have you ever heard of the Roman coin IQ test?". They will say they haven't.
- Explain to them; "The ancient Romans used to think that intelligence depended on the size of the brain. To test someone's intelligence they would take a coin, press it against their forehead and have them hit themselves on the back of the head, trying to knock it off. They they thought that people with larger brains had them pressed tighter against their skulls, so the shock of hitting the back of your head would carry through easier and knock the coin off. They counted how many hits it took to knock the coin off, and the less hits it took the smarter you were."
- Take out a coin. Frown and squeeze your eyes shut tight (it's important you do this so when you tell your victim to they won't be suspicious). Then press the coin against you forehead, take your hand away, and open your eyes.
- Hit yourself on the back of the head, counting each hit, until the coin falls off.

Step 3: Executing the Prank

- Ask your victim to try. They will be likely to agree, as they will probably want to beat your score.
- Tell them to frown and squeeze their eyes shut. If they ask why, say something like "you need to do it to get the skin on your forehead tight so the coin sticks.".
- Press the coin hard against their forehead and carefully pull it away. They should feel like they have a coin stuck on their forehead.
- Tell them to open their eyes and start hitting themselves on the back of the head. If you want, pass them things that won't hurt them to hit their head with.
- When you feel like they've had enough or they seem really frustrated, show them the coin and explain.



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    12 Discussions


    5 years ago on Introduction

    Our physics teacher did this trick to an student who was talking all the time, we couldn't stop laughing when we saw him hitting the back of it's head thinking the coin was still there.

    1 reply

    5 years ago on Introduction

    Awesome. This probably won't work on my younger brother though, he knows my body language when I am pulling crap, haha. He's constantly suspicious of me when try to convince him to do arbitrary things like this. But sometimes, I can whip up a good cover and convince him. Maybe I can pull it off.

    2 replies

    Reply 5 years ago on Introduction

    Good luck! Telling the Roman story usually convinces people.


    Reply 5 years ago on Introduction

    I think you're right. If I go on long enough with a story, and don't contradict myself, he usually falls for stuff.


    6 years ago on Step 3

    I had another thought - don't know if it would work.

    have a spare coin in your hand - make the one on their head sticky on the back so it stays put when bashed the first time - as soon as they do the first hit say "wow your really intelligent" show them the coin in your hand (spare coin) - they still have the sticky coin stuck to,their head - this would be funny as anything if ya did it in a coffee shop in a mall, quiet table, no one looking - do the trick and they feel all smug n happy - get up and walk out - see how far ya get with folks wetting themselves laughing at your friend before they realize.

    Loved this - I have a victim in mind already.


    1 reply

    Reply 6 years ago on Step 3

    Haha that's a great idea! I can picture someone walking around my school with a coin stuck to their head, getting all kinds of looks.


    6 years ago on Introduction

    Any ideas for a better title and main image?