Party Foul
Take advantage of the fact that your friends still use solo cups and create a hole in the bottom of the cup so that the perimeter of a straw fits in perfectly. Fill the cup up with your jungle juice concoction (around the straw). Your victim will obviously be thrown off by a straw in the solo cup (so weird) and remove it, thus opening the hole and having that nice fruity poison stream down onto their shoes. An obvious party foul.
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