There's no need to bring beer and a cooler to your picnic. With a few modifications, you can turn the box of any case of beer into a simple ice chest.
If you're trying to save packing space -- or just forgot to bring the cooler -- YouTuber DaveHax demonstrates a perfect alternative in this video. Cut open the top of the box to make a lid, pull all of the beer out, line it with a plastic bag, and put the beer back in. Now just add plenty of ice and your beer will stay nice and cool for hours. No extra equipment needed.
Cold Beer - Simple Cool Box Life Hack [YouTube]