Vocath's Bottle Rockets

You create 3 tiny rockets like bottle caps.  They hang in the air sizzling like fireworks.  The player aims the darts at a single creature.  Each dart hits a creature of your choice that you can see within range one per round. A dart deals 1d4 + the caster's modifier force damage to its target. At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the spell creates one more dart for each slot level above 1st.  These rockets follow the creatures movement through teleportation circles, doorways, around corners through portals if at all possible.  If completely blocked they strike whatever is in their way and do the damage to the blockage.  Otherwise they continue to hit even after the creature is down.