Debris Barrier

You animate non-living chunks of space debris into motion. The debris must already be present and is the material component for the spell. The debris creates fast moving rings around the caster that deal 4d4 bludgeoning, piercing, or slashing damage (depending on the type of debris) to any creature that moves through the rings or starts their turn within 5 ft of the rings. You can use a bonus action to adjust the radius of the rings up to a maximum of the spell's range. The animated debris returns to its inert state in the presence of a successful dispel magic.

This spell is inspired by page 72 of the 2e AD&D book titled Spelljammer: Lost Ships by Ed Greenwood.