Seal of Primordium

Enchantment

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

2004-10-04:
This is not modal. If the target changes from an artifact to an enchantment or vice versa, this still destroys it.
2017-03-14:
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.