Choose one — • Counter target spell if it's red. • Destroy target permanent if it's red.
"Heed the lessons of our time: the forms of water may move the land itself and hold captive the fires within." —Gustha Ebbasdotter, Kjeldoran Royal Mage
2004-10-04
The decision to counter a spell or destroy a permanent is a decision made on announcement before the target is selected. If the spell is redirected, this mode can't be changed, so only targets of the selected type are valid.
2016-06-08
Hydroblast can target any spell or permanent, not just a red one. It checks the color of the target only on resolution.