Magic Hovermissile (3.5e Spell)

The best counterspells don't wait on you.

You send out a large magical missile to hover around the chosen target. When the target begins performing an action that requires concentration and takes a standard action or longer, the missile smashes into them, dealing 3d4+3 points of force damage, plus 1d4+1 damage for every two levels beyond 5th. Spell resistance is rolled when the missile strikes, not when this spell is cast.

The missile strikes unerringly, even if the target is in melee combat or has less than total cover or total concealment. Specific parts of a creature can’t be singled out. Inanimate objects are not damaged by the spell.

If the missile is not triggered during the duration, it is wasted.