Nivea, Beloved Battlemage [Mystery Booster: Commander Edition]

Whenever a creature you control becomes blocked, you may untap it and remove it from combat.
{5}{W}{W}{W}, Sacrifice Nivea: Create an Akroma, Angel of Wrath token. (She's a {5}{W}{W}{W} legendary 6/6 Angel creature with flying, first strike, vigilance, trample, haste, and protection from black and from red.)