SLD: Mikaeus, the Unhallowed Kids Puzzle Spend this mana only to

Spend this mana only to cast an Elemental spell or activate an ability of an Elemental

if you listen closely

public and private contracts they acquired

prior to the bridge’s opening

return target nonland permanent card with mana value 3 or less from your graveyard to the battlefield with a finality counter on it

SLD: Mikaeus, the Unhallowed Kids Puzzle Spend this mana only toIntimidate (This creature can't be blocked except by artifact creatures and or creatures that share a color with it.) Whenever a Human deals damage to you, destroy it. Other non Human creatures you control get +1 +1 and have undying. (When a creature with undying dies, if it had no +1 +1 counters on it, return it to the battlefield under its owner's control with a +1 +1 counter on it.)