Seal of Primordium

• WWizards of the Coast2004-10-04
  Official Ruling
  This is not modal. If the target changes from an artifact to an enchantment or vice versa, this still destroys it.
• WWizards of the Coast2017-03-14
  Official Ruling
  You can activate Seal of Primordium's ability targeting Seal of Primordium itself if you want it to leave the battlefield. This is because targets are chosen before costs are paid. The ability won't resolve as it tries to resolve.

Rulings via Scryfall