Triggering Touch

Touch any object with your open hand, a stone on the ground, a dagger, an arrow, a piece of armor, ext. After releasing the object, using the same hand, form a sideways fist with the thumb raised slightly above it with in three seconds of touching the object. When thumb is lowered onto the fist, an explosion occurs on the area of the object you touched dealing 2d8 force damage with an additional d8 per spell level. Spell has a functional range of 70 feet and can not be triggered from farther away, but can still be triggered caster reenters range within 1 hour. If not the spell becomes null and spell slot is waisted. Explosion range 15 feet and half damage is dealt for an additional 10 feet.