Magma bursts from the ground in a 20-foot radius, 40-foot-high cylinder centered on a point you can see within range. Each creature in the radius must make a Dexterity saving throw, taking 6d6 fire damage on a failed save, or half as much damage on a successful one. The ground in the area is considered difficult terrain for the duration.   Each round you maintain concentration on this spell, the eruption produces additional effects on your turn.   Round 2. Clumps of dirt and rock dislodged by the explosion fall from the sky. The area in the cylinder becomes lightly obscured. Each creature in the cylinder must make a Dexterity saving throw. On a failed save, a creature takes 3d6 bludgeoning damage and becomes restrained until the spell ends. On a successful save, it takes half as much damage and isn’t restrained. A creature restrained this way can make a Strength saving throw as an action on its turn, freeing itself on a successful save.   Round 3-5. Poisonous volcanic gas floods the area. The area in the cylinder becomes heavily obscured. Each creature in the cylinder must make a Constitution saving throw. On a failed save, a creature takes 1d6 fire damage and 1d6 poison damage, and is poisoned for 1 minute. On a successful save, it takes half as much damage and isn’t poisoned. If a creature enters the area for the first time in a turn while the gas persists, it becomes subject to the effect. A creature poisoned this way makes a Constitution saving throw at the end of each of its turns, ending the condition on a successful save.   Round 6-10. The same as Round 3-5, but the targets make their initial Constitution saving throw against the effect each round with advantage.