Bjarzura's Rat Swarm

You call forth a swarm of rats at your position. As a bonus action, you are able to controll the swarm and percieve, what they see and hear. The rats are able to move around until their distance to you extends above 500 ft., at which they disappear. They also disappear after 1 hour or if you loose concentration.

The rats are able to attack a creature and force it to make a dexterity saving throw. They take 6d4 piercing damage on a failed save or half as much on a successful one. On a failed save, the rats stick to the target, dealing an additional 6d4 piercing damage at the start of the creatures turn. The creature can repeat the saving throw after the damage is dealt to them, ending the effect on a success and placing the rats in an unnocupied space within 5 ft. of the creatures choice.

The swarm can be split up into up to three equally sized, smaller swarms. The damage is split up in the same way and all swarms can be given orders in the same bonus action.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the piercing damage increases by 2d4 and the maximum distance increases by 200 ft. for each slot level above 5th.