Assegai of Space

Bolts of Hardened Nebulaic Vapor with dimensions of 4' - 6'' x 0' - 3'' appear at the target location. The max amount of bolts one may summon in a turn is 4, to a maximum of 12 in total. Each Bolt has a base speed of 50ft and are able to pierce most  barriers but are stopped by 

When you cast the spell, choose a point you have seen before and summon up to 4 Bolts of Vapor that will steer towards the target and around obstacles it can't pierce. The creature  must make a Dexterity saving throw. A creature takes 4d10 + 10 piercing damage and becomes restrained on a failed save, or half as much damage on a successful one. 

If you are in a location where you can see the sky, The Bolts length is increased to 8ft while damage increases by 1d12

At Higher Levels. When you cast this spell using a spell slot of 5th or higher level, the damage increases by 1d10 for each slot level above 4th.