This easy prank will give your "victim" a really nasty, bitter taste when they brush their teeth. It is 100% safe, and reversible. The taste will go away after a few hours, and to clean the toothbrush, you only need to rinse it in water for about 30 seconds.
Let's Get STARTED!

Materials:
•A disposable cup
•The victim's toothbrush
•White Vinegar (Balsamic will stain the toothbrush, which will arouse suspicion)
•Toothpaste (for the victim to use)

Step 1: Add Vinegar to Cup

Pour some vinegar into the disposable cup, adding enough to submerge the toothbrush's head. Adding too much won't do anything, except maybe waste vinegar. DON"T WASTE.

Step 2: Put Toothbrush Into the Vinegar

Put the toothbrush into the vinegar, and swish for around 30 seconds.

Step 3:

Put the toothbrush back where you found it, and wait. Eventually, your victim will brush their teeth, and wait for a "Blechhh" sound coming from the victim. This means the prank worked. Casually walk over, and ask if anything's wrong. Tell them something like you "just scrubbed the toilet with the toothbrush", or something like that.

**The toothpaste reacts to the vinegar, to make a really bitter taste**
**This is completely safe**