I have been picking my brain for awhile on how to perform a really cool car prank. I came up with this idea.
1) Hot Water Bottle - $6
2) 2" to 3" hose clamp - $1
3) Some gaff tape - $10
All you have to do is secure the hot water bottle to the tail pipe of a car for this prank. It is important that the car is single exhaust (unless you want to double the cost and do it to both pipes) and the tail pipe has a diameter of approx. 2 to 3 inches. This is because all hot water bottles seem to have a 2 to 3 inch flap on the end. Once you get the clamp secured, fold the hot water bottle under and tape it to the exhaust. Make sure and only put a little tape as you want the bottle to come undone and pop up when it is pressurized.
Once the car is started, the victim should notice a lack of power immediately. Then when things look like they can't get any worse, a large explosion occurs.
The more gas that is given, the quicker the bottle will fill up and explode. At a idle, this video shows the bottle explode in about 30 seconds.
This video is for demonstration purposes only. Bodily harm might occur if this prank is performed wrong. Mechanical problems could occur if this prank is performed wrong.
Here is the video demonstration: