Tentacle Lash

Your arm elongates, into a long, wet, suckered tentacle. When you cast this spell and as an action on each of your spells you can perform a melee spell attack against a creature within 30 ft. On a hit you deal 4d10 bludgeoning damage and the target must make a Strength saving throw if it is Huge or smaller. On a failure you may choose one of the following effects:

• The target is knocked prone
• You disarm the target; you take one item or weapon the target is carrying or wielding (and that is not fastened, e.g. armor) and return it to your person.

The tentacle also serves as a useful appendage that can be used like a grappling hook or rope at the DM's discretion.

Credit goes to Humperdink's Ware for coming up with this idea.