[Bruno]

Missile Shield is one of those defenses that protects against a description, not a game mechanic.

"Lasers" aren't a game mechanic, they're a description. Burning attacks could be lasers, corrosion attacks could be lasers, cutting attacks could be lasers - DR vs Lasers would protect against all of those, but not against torches, acid, or knives.

Missile Shield protects against missiles. "Is it an Affliction" is the wrong question. "Is the affliction a missile?" is the right question. Go back to how you described the ability in the first place and check that.

When you create an ability, there's various descriptive elements that can be game mechanically important but aren't in themselves game mechanics.

"I shoot jets of fire out of my hands" - Well, now this attack can be stopped by DR vs Fire, and you can stick your hand over a wall and shoot without exposing your head, but if you're tied up, you'll have a lot of trouble aiming. It also has an extra impact on creatures with Vulnerability to Fire, or who's Regeneration or Unkillable have an Achilles Heel to Fire.

They could also be balls of magma or really really hot embers - the embers are probably stoppable by missile shield, not sure about the magma.

The affliction could be bolts of magic, poison darts, or an enchanted slingstone made out of the brains of your enemies (thanks, ancient Celts). The darts and slingstone would be missiles, the bolts of magic perhaps not.

Details matter.