Leaky Coke Can Prank

This instructable will show you how to modify a drinks can so that when your friend, colleague or family member takes a swig from their delicious soft drink (or beer), water falls out the bottom and soaks them.

This prank works by cutting a hole in the bottom of a can identical to your friend/colleague's favourite drink and installing a plastic cup inside. When they're not looking you can swap out their drink for your modified one and sit back and watch the confusion/laughter/anger.

It works best when they're sitting down at a desk or on a sofa as the water will fall out when they lower it after trying to take a drink, causing water to fall on their lap.

It is intended as an easier to make version of my other coke can prank, the Laughing Coke Can as it requires no electronics knowledge, just 15 spare minutes.

Materials Required:

- 2 drinks cans
- superglue (optional)
- double sided tape
- large/tall cap or container
- syringe (not needle)
- 5cm tubing (or USB cable)

Tools Required

- hammer
- hacksaw blade
- punch (or thick nail)
- tin snips (or strong scissors)
- pliers

Step 1: Make a Hole

For this step you'll need a hammer, punch (or thick nail) and hacksaw blade.

With the punch and hammer, make a hole near the edge big enough to insert the hacksaw blade.

Holding the hacksaw blade carefully, saw around in a circle close to the rim of the can. Get as close as you can to the rim near the side that has the drinking hole on it.

Step 2: Add a Container

For the prank to work, a container is required to hold the liquid that will pour out the bottom when the can is tilted.

Anything less than the diameter of the hole in the bottom of your can (44mm) would be good. Mine's the cap from a sun cream bottle. You could use anything of that size. e.g plastic shot glass, plastic measuring cups from Schweppes soft drinks, large bottle caps or a film canister (if you're old enough to remember those). The more liquid it holds the better.

I decided to mount it to a piece of another can so I could get it to stick well before I put it in the can. Previous attempts without the can segment resulted in wonky or wobbly containers. This way I could check it was firmly attached and once the can segment was inside, it could only stick in the right place.

With some tin snips or very strong scissors, cut down the length of the second can. Remove the top and bottom to leave you with a roll of aluminium. Neaten this up with your tin snips or scissors.

I attached the cap to the can segment using super glue and stuck double sided tape to the back of the can segment.

Before removing the tape backing, check it will fit through the hole then remove the tape backing and insert through the hole in the bottom of the can. When it's stuck you want the water container to be situated on the side opposite to the drinking hole.

Step 3: Fill 'er Up

To get the water inside the container easily use the non plunger part of a syringe. Most pet stores sell these to help you worm your cat or dog.

Take a length of old wire. Mine was a short length of USB wire. Pull the wires and protective sheath from the middle and save for another project.

Push the tube over the end of the syringe. If it's slightly too small, warm it with a lighter to make it easier to fit.

To fill, push your filler through the hole in the top of the can and make sure the end of the tube is in the container. Fill from a tap until the container is full.

You're now ready to swap it out for your friend/colleague's can. Make sure you swap like for like cans or they'll notice straight away. If at a party, why not offer your mate a beer? You can fit a taller container in a beer can, and more water means a wetter friend! If they're sitting down they'll get more on them.



    • Growing Beyond Earth Maker Contest

      Growing Beyond Earth Maker Contest
    • Pets Challenge

      Pets Challenge
    • Frozen Treats Challenge

      Frozen Treats Challenge

    11 Discussions

    Ole bally

    8 years ago on Introduction

    Fun way to prank your mates is let him drink the first 1/4 of his beer (out of the can) then wait for him to go to the toilet. grab his beer and using a sharp knife make a little hole about an inch down from the opening. As he drinks the liquid drips out of the hole and confuses and embarrasses the heck outta him!


    9 years ago on Introduction

    Nice work, It could do with a bigger reservoir really.. I know that makes it harder to get into the can. You can get those safety tin openers, that would allow you to open the bottom, and easily glue it back in place.

    5 replies

    Reply 9 years ago on Introduction

    I toyed with the idea of making one from plastic but it wouldn't have been much bigger because of the diameter that can fit through the bottom. After filling my resevoir with water and chucking it on my lap I decided the 50ml cap I had would be plenty. It leaves quite a mark!


    Reply 9 years ago on Introduction

    I was thinking more in terms of a weight difference if the can was replaced.


    Reply 9 years ago on Introduction

    That's a good point. I hadn't thought of that, I just picked it up and used it. I'll experiment with adding some weights under the container before installing it. I have some plastic coated lead fishing weights somewhere.


    Reply 9 years ago on Introduction

    Yes... Let's put some lead into your friends drink! Instant party!


    Reply 9 years ago on Introduction

    didnt he say plastic coated? unless lead is bare and nothing protecting it its posionouse with protection its fine