From the dawn of time, humans have wanted to know how to live forever. After all, the end is a frightening, unknown thing, and a chance to avoid it entirely is almost too enticing to pass up.
Nearly every culture throughout history has fantasized and written stories about what it might be like to skip the whole "involuntarily releasing your bowels as you die" trope. Whether they attempt to sell their soul to the devil or perform daily pilates (or both, simultaneously), everybody has their own way of staving off the Grim Reaper just a bit longer.
The bad news is many of the ways to become immortal come with pretty nasty side effects. But hey, if you think becoming a flesh-eating zombie is worth it for the chance to live for eternity, then maybe you should give one of these methods a try.