Your coworkers are in for a bit of a surprise when you scrape the icing out of the centres of a box of cookies, and carefully replace it with peppermint toothpaste. Not quite the same treat they'll be anticipating.
Ready to get a bit messy? Cut off the top layer of your friend or family member's deodorant, and replace with a layer of cream cheese. Place it back in the washroom with the lid on, and wait for them to be fooled (we think you'll hear the reaction on this one)!
Put a raisin into a toothpaste tube then cover it up with more toothpaste. The idea here is when your friend or family member squeezes out the toothpaste, they'll think the raisin is a bug.
This one's a bit time consuming, but worth it! Completely cover a bar of soap with clear nail polish and let dry, then replace in its usual spot in the washroom. When someone tries to use it, they'll be scratching their heads wondering why it won't lather.