Delayed Blast Fireball
If touched before the spell ends, the creature touching the bead makes a Dexterity saving throw or the bead detonates. On a successful save, the creature can use an action to throw the bead up to 40 feet, moving the area with it. If the bead strikes a creature or solid object, the bead detonates.
The fire spreads around corners, and it damages and ignites any flammable unattended objects in the area.