Edna Purviance

Defender
{2}: Edna gains +1/+1 and may attack. More than {2} cannot be used. At end of turn in which Edna attacked, tap Edna. She doesn't untap during your next untap phase.
{1}{w}{u}: Untap Edna. She is Defender again.
{t}{w}{u}: Target attacking black creature's power is 0.