Reia Grata, Fog Mother

+2: Put at a 0/1 Fog creature token with "{t}: tap target permanent your opponent controls." onto the battlefield.
-2: Sacrifice a Fog creature token you control, your opponents cannot untap nonland permanents on their next untap step.
-4: You get an emblem with: "If a source would deal damage to you prevent X of that damage where X is the number of Fog tokens you control."