Arcane Mage CR that only casts Arcane Explosion

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I'd like to create a CR for an Arcane Mage that will be used for Dungeon Boosting low level characters.

Here's what I'm looking to create:

A CR that will run through a dungeon casting Arcane Explosion and only arcane explosion.
The CR must be able to move to mobs to make sure Arcane Explosion hits the intended targets.
Cast Defensive CD's if needed.

I think this would be the absolute fastest way to boost characters through lower level dungeons.

Any help would be greatly appreciated.