Take a balloon and fold it lengthwise.
Trim off the neck of the balloon. Make another cut about a third of the way down on the opposite end, as well.
Pull the cut balloon over the bottom of the mason jar, making sure the smaller hole is on the bottom. If you don’t have someone to help hold the jar while you apply the balloon, just place the jar in between your knees to stabilize it.
You can now use it as a centerpiece and put flowers or even candles. It’s also the perfect glass for drinking cocktails and other beverages.