Dread Cacodemon

Oracle Text

When Dread Cacodemon enters the battlefield, if you cast it from your hand, destroy all creatures your opponents control, then tap all other creatures you control.

Card Rulings

9/22/2011 If you put Dread Cacodemon directly onto the battlefield from your hand, perhaps because of Kaalia of the Vast’s ability, its ability won’t trigger.
9/20/2013 If a creature (such as Clone) enters the battlefield as a copy of this creature, the copy’s “enters-the-battlefield” ability will still trigger as long as you cast that creature spell from your hand.