Kryptonite

Kryptonite showers across the multiverse!
Unfortunately, the Deck of Fate has made
you weak to the substance. If you are within
100' of it, you lose 1/2 your attacks, combat
bonuses, attributes & saving throw bonuses!
Even worse, it just so happens one of these
rocks just landed near you as it fell from the
sky. This could reveal your weakness to
others, including any enemies watching.