Ceradanu's Gravity Well

You throw a a small black bead at a Target. 
Upon hitting the Target an intense force of gravity centered on them is made. 
anything withing a 10' Radius that is not tied down or worn is pulled towards the Target.
The Target and any Creature within the area of affect has 1/2 Movement for the Duration or until the spell ends.
Any Creatures who Start their turn or enter the area for the first time must make a Str Save vs your spell DC. 
On a fail the Creature is pulled into the Target for 4d6 Force Dmg to both the target and the Target of the spell. 
While under this spell, any projectile ATK has ADV, if missed make another attack against another creature if it failed its save.