After you've tried out Nextraker's pillow prank, move onto the medicine cabinet with this deodorant stick prank. All you need is your victim's stick of deodorant (white) and some Kool-Aid (or in this case Flavor Aid).
Simply open the Flavor Aid packet and spread the drink powder onto the top of the deodorant. You have to make sure the crystals are the same color as the deodorant, otherwise it will be obvious. After you've rubbed it all in, hide it back where it belongs and wait for them to use it. They'll get "red" with anger once their armpits are stained (and not with sweat!).