Suicidal Charge

Oracle Text

Sacrifice Suicidal Charge: Creatures your opponents control get -1/-1 until end of turn. Those creatures attack this turn if able.

Card Rulings

2/1/2009 Suicidal Charge’s ability affects only the creatures your opponents control at the time it resolves. If another creature comes under the control of one of those players by the time that turn’s combat step begins, it won’t have to attack.