Abyssal Pull

A spell gained through great sacrifice, casted at will, when cast the caster's eyes turn black, laying the spell's demonic influence plain for all.
In a 30ft radius, the ground turns to a circle of black tar. Those inside must pass a dex save or be immobilised as black tar hands reach up, grabbing the targets and bringing them down to the void below. For one turn those targeted are unable to take any action and will take necrotic dmg (roll dmg), if they do not succeed on a str save the next turn, they are pulled into the abyss, never to be seen again with only their items floating back up to the surface.