Vanguard of Crabs

You call forth unusually large crabs to protect you.  They crawl around you to a distance of 20 feet for the duration. 

The area counts as difficult terrain for the duration, and when a creature enters the area for the first time on a turn or starts its turn there, it must make a Dexterity saving throw.  On a failed save, the creature takes 4d8 slashing damage.  On a successful save, the creature takes half as much damage. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.