Stomatocyte

On your opponent's upkeep, take a random card
from their hand, reveal it, and that card must always be
shown in the hand.
This particular artifact is a monocle and has quite an interesting story surrounding it. It once stopped the blade
of the most feared swordsman in all the land just
enough for his prey to strike back. Before drawing his
final breath the swordsman cursed his prey. He cursed his prey's bloodline with the failure of K+ and Na+ pumps which will increase H2O leading to swelling