Gravity Bomb

You can use an action to throw this bomb
at a point up to 60 feet away. When it reaches
the end of its trajectory, the bomb detonates
in a wave of powerful gravity. Each creature
within 15 feet of the detonation must succeed
on a DC 13 Constitution saving throw or be
pulled to its center.If multiple creatures are
affected by this, they are are moved as close to
the center as possible. A creature that failed
the save by 5 or more is knocked prone as well.