If a creature you control would untap during your untap step, put two +1/+1 counters on it instead. Whenever chaos ensues, untap each creature you control.
2012-06-01
If you untap a creature you control during another player's untap step (perhaps due to Seedborn Muse's ability), that creature will untap normally. You won't put any +1/+1 counters on it.
2012-06-01
Other spells and abilities can untap creatures as normal. In that case, they'll just untap. You won't put any +1/+1 counters on them.
2012-06-01
While Edge of Malacol is face up, the normal turn-based action of untapping your creatures is replaced. Those creatures won't untap. Other tapped permanents you control will untap as normal.