Amulet of Whirlwinds

This amulet is strung on a brass necklace and holds a piece of djinn magic. The amulet has 9 charges. You can use an action to expend 1 of its charges to create a whirlwind on a point you can see within 60 feet of you. The whirlwind is a 5-foot-radius, 30-foot-tall cylinder of swirling air that lasts as long as you maintain concentration (as if concentrating on a spell). Any creature other than you that enters the whirlwind must succeed on a DC 15 Strength saving throw or be restrained by it. You can move the whirlwind up to 60 feet as an action, and creatures restrained by the whirlwind move with it. The whirlwind ends if you lose sight of it. A creature within 5 feet of the whirlwind can pull a creature out of it by taking an action to make a DC 15 Strength check and succeeding. A restrained creature can try to escape by taking an action to make a DC 15 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the whirlwind. When all of the amulet's charges are expended, the amulet becomes a nonmagical piece of jewelry worth 50 gp.