This homebrew was made by u/Monkey_DM on Reddit, who has given clearance for a port by me to DnDBeyond.

Select a point within range. In a 10 feet radius centered on that point the gravity increases, causing immense pressure to be applied to all within. When a creature enters the area for the first time on a turn or starts its turn there, it must succeed a Strength saving throw or have its speed reduced to 0. On a successful save, the creature can move freely.

On subsequent turns as a bonus action, you can move the sphere us to 20 feet in any direction.

When you cast this spell using a spell slot of 3rd level or higher, the radius increases by 5 feet for each slot above 3rd.