SCP 2935 O Death

{t}: Add {c}
{3}, {t}: Put a death counter on target creature,
then return it to it's owner's hand. Counters
stay on that card as it moves between zones.
Any player may activate this ability.
Whenever a card with a death counter enters the
battlefield, each player discards their hand and
mills their entire library. Exile all graveyards and
all permanents not named SCP 2935 O Death.
Each player loses life equal to their life total.