Blast everything nearby with an explosion of elemental magic.
Damage all other creatures in a 5 ft. burst (3x3 space (15 ft. x 15 ft.) square) centered on you.

Fail:
Creatures which fail their health save are pushed 5 ft. away, regardless of size.

(If the target would be pushed into a mortal hazard which would cause it to instantly or imminently die, such as off a cliff, it gets a health save to avoid being moved into that hazard, but is still moved as far as safely possible.
Being pushed does not provoke attacks of opportunity.)

Pass:
Creatures that pass their health save take half damage.

Intensify:
When you Intensify this spell, you may add +5 ft. to the burst area per level of Intensification.

You may protect an ally caught in this spell’s area from suffering its effects by passing a DC 15 test of Spellcraft. You may try this for each ally in the spell’s area.
(This only protects them from that one casting of this spell, not all future castings.)

Suggested Backfire: The spell blows up in your face. You take the full damage unless you pass a health save to half it. Noone else is affected.

Affinity:
When you learn this spell, choose which element your Arcane Bursts are.
Whenever you cast this spell, it will normally be of that element.
You can try to cast this spell using a different element, but must pass a DC 20 test of Spellcraft each time to change the element from what it normally is.

You overcharge your Arcane Burst spell, dramatically increasing its power.
Creatures have disadvantage on their saves against your Arcane Burst.
Add +15 ft. to the burst size of your Arcane Burst.

Any creature which fails its save against your Arcane Burst is pushed out of the spell’s area.
For every size bigger than medium the target is, it is pushed 5 ft. less.
(Relevant Sizes: Medium, Large, Huge, Giant)

(If the target would be pushed into a mortal hazard which would cause it to instantly or imminently die, such as off a cliff, it gets a health save to avoid being moved into that hazard, but is still moved as far as safely possible.
Being pushed does not provoke attacks of opportunity.)