2005-06-01 : Will not generally kill zero cost creatures because the age counters go on before the ability triggers. If would be possible if something like Power Conduit were removing counters.

2008-04-01 : If you don’t pay the cumulative upkeep, you’ll sacrifice Wave of Terror before your draw step begins. It won’t destroy any creatures that turn.

2008-04-01 : This destroys creatures with converted mana cost exactly equal to the appropriate number, not equal to or less than that number.