Necklace of Fireballs

This gorgeous necklace is affixed with 1d6+3 beads that radiate power. You can use an action to hurl a bead up to 60 feet. When the bead lands it detonates as a 3rd-level __fireball_ (save DC 15). You can hurl multiple beads with the same action, increasing the spell level of the __fireball_ by 1 for each bead beyond the first.