Quantum fluctuations.
With the multiverse where there could be pockets of the universe that are expanding with no knowledge of any other pockets of the universe. These are essentially independent universes from one another. Quantum fluctuations. Would be responsible for a other universe having slightly different laws of physics. You’d have to find some way to tunnel from one universe to the other, but that could be very dangerous.
Then you could just dissolve into a pile of goo.
And all of your biochemistry would change.
