Pyroblast

• WWizards of the Coast2004-10-04
  Official Ruling
  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.
• WWizards of the Coast2016-06-08
  Official Ruling
  Pyroblast can target any spell or permanent, not just a blue one. It checks the color of the target only on resolution.

Rulings via Scryfall