Nosoi, Devkarin of Svogthos

When Nosoi, Devkarin of Svogthos enters the battlefield each player puts the top eight cards of
their library into their graveyard.
Each creature card in all graveyards have
scavenge. The scavenge cost is equal to its mana
cost, you may activate scavenge from any
graveyard as if it were your own. (Exile a
creature card from your graveyard and pay its
mana cost: Put a number of +1/+1 counters
equal to that card's power on target creature.
Scavenge only as a sorcery.)