Spectral Bears

Oracle Text

Whenever Spectral Bears attacks, if defending player controls no black nontoken permanents, it doesn't untap during your next untap step.

Card Rulings

8/1/2008 The checks for black cards is made both at the time you declare attackers and as the ability resolves. If there are any at the time attackers are declared, it won’t trigger at all. If there are any at the time it resolves, the ability will do nothing.