Cinder Cone Eruption

You press your hands to the ground and create a subterranean fissure, agitating the primordial fires of the world's depths and guiding them as they burrow to the surface. Choose a point you can see on the ground within range. A volcanic vent erupts in a 10-foot cube centered on that point. Each creature in that area must make a Dexterity saving throw. A creature takes 5d10 fire damage on a failed save, or half as much damage on a successful one.

120 feet above the center of the vent, a cloud of ash appears in the shape of a cylinder that is 30 feet tall with a 60-foot radius for the next 10 minutes. If the space above the vent can't accommodate the cloud, the obstructing area above the vent takes 5d10 fire damage until the spell ends or there is enough room for the cloud to appear.

After the cloud forms, for the remainder of the spell's duration, the volcanic vent ejects a lava bomb at the start of your turn which falls at the end of your turn on a random point within 5 feet of a creature, object, or structure beneath the ash cloud. Each creature within 5 feet of that point must make a Dexterity saving throw. A creature takes 5d10 fire damage on a failed save, or half as much damage on a successful one. While you maintain concentration on this spell, you can use your action to choose the point beneath the cloud where the lava bomb falls. If you lose concentration, the volcanic vent remains but becomes uncontrollable for the remainder of the spell's duration.

Non-magical objects and structures in areas affected by this spell take the damage rolled without making a save and ignite if flammable. When the spell ends, over the next hour the cloud drifts to the ground, burying the area in a layer of ash and pebbles which forms a 30-foot high conical hill.