Chaotic Field

You direct an immense amount of energy into a point you can see within 120 feet of yourself. Immediately, every space within 25 feet of that point is plunged into magical chaos. For the duration of the spell, that area is considered difficult terrain, and creatures of your choosing must succeed a Wisdom saving throw to leave the area. Upon casting, roll 2d8 and roll 4d4.

Choose one of the d8s, and the effect of the spell is determined by the number rolled on that d8. If both d8s land on the same number, double the radius of the spell and reroll. This can happen an indefinite amount of times. 
1: A violent sound erupts from the center of the spell. All creatures within the area must make a Strength saving throw, taking Thunder damage equal to the total number rolled on the dice, being pushed 30 feet away, and being knocked Prone on a failed save, or taking half as much damage only on a successful save. This will not override the Wisdom saving throw to escape, however a creature pushed to the edge of the field 
2: The area is plunged into darkness. The area is considered magical darkness until the start of the next turn. Each creature of your choosing in the area must make an Intelligence saving throw, taking Psychic damage equal to the total number rolled on the dice and being forbidden from attempting to leaving the area on a failed save, or taking half as much damage only on a successful save. 
3: A virulent gas fills the area of the spell. All creatures within the area must make a Constitution saving throw, taking Poison damage equal to the total number rolled on the dice and being Poisoned for one minute on a failed save, or taking half as much damage only on a successful save. 
4: The area is obscured as if within a storm cloud as lightning streaks about within the area. The area is considered Heavily Obscured until the start of the next turn. All creatures within the area must make a Dexterity saving throw, taking Lightning damage equal to the total number rolled on the dice and having disadvantage on any concentration spells on a failed save, or taking half as much damage only on a successful save.
5: Hundreds of miniature planar blades slash within the area. You make an attack roll against all creatures of your choice, dealing Force damage equal to the total number rolled on the dice and reducing the number rolled on one of the hit creature's ability checks or saving throws by 1d10, so long as you do so before the end of your next turn.
6: Flames erupt from the outside barrier of the field. All creatures within the area must make a Strength saving throw, taking Fire damage equal to the total number rolled on the dice and being pushed 10 feet towards the center of the field on a failed save, or taking half as much damage only on a successful save.
7: A sleet storm begins battering all within the field's area of effect. All creatures within the area must make a Constitution saving throw, taking Cold damage equal to the total number rolled on the dice and being hindered by ice on a failed save, or taking half as much damage only on a successful save. A creature who is hindered by ice has the Restrained condition until it or another creature makes an attack roll on the ice to free the creature (AC 8, immunity to Cold, Poison, and Psychic damage, 1HP so resist/vulnerability doesn't matter). 
8: Acid flows around the entire area. All creatures within the area must make a Dexterity saving throw, taking Acid damage equal to the total number rolled on the dice and, if they are wearing physical armor, having their armor corroded on a failed save, or taking half as much damage only on a successful save. A creature with its armor corroded has its AC reduced by two until the armor is repaired. If the armor has its base AC reduced to 9 or below in this way, the armor is destroyed unless it is magical, in which case it must be repaired.

So long as concentration remains, you can use your action to reroll the dice and apply the new effect. If you do not do so, the field becomes dormant so long as concentration remains, still requiring the wisdom saving throw to leave but not having any effects active. The field remains dormant until you use an action as described previously to reroll the dice and apply the new effects. 

Using higher spell slots. Roll an additional 1d8 for every level used to cast this spell above 5th. This does not affect the original expansion ruling, in that only two of the d8s must land on the same number for the field to expand.