I've recently started a new campaign centered around spellcasters; think murderous hogwarts. THe DM has said we'd eventually get to create our own spells.
I'm playing magus, and there's one spell that has always bugged me: detonate.
A 10d8 explosion seems cool, until you realise you hurt yourself, it has a material cost, and only goes of one turn after you cast it. But I like the idea of a "explosion" spell. So I though of this:
Last resort
School evocation [acid, cold, electricity, or fire]; Level sorcerer/wizard 5
Casting Time 1 standard action
Components V, S, M
Range 30 ft.
Area 30-ft.-radius spread centered on you
Instantaneous
Saving Throw Reflex half; Spell Resistance yes
You flood yourself with a potent surge of elemental energy. As the charge of a touch spell, you can decide to release the energy as a free action.
When this spell creates the explosion of energy, choose one of the following four energy types: acid, cold, electricity, or fire. The explosion inflicts 1d8 points of damage of that energy type per caster level (maximum 10d8) to all creatures and unattended objects within 15 feet, and half that amount to targets past 15 feet but within 30 feet. You automatically take half damage from the explosion, without a saving throw, but any other energy resistance or energy immunity effects you may have in place can prevent or lessen this overflow damage caused by the explosion.
Any creature caught inside the blast is staggered for 1d6 rounds, reflex save for all EXCEPT the caster.
So what I did was boost the spell up a level, remove the material component, and added a "staggering" that the caster can NOT avoid.
Maybe the staggering should be longer? Maybe it should be a higher level? I was curious as to what someone more experienced would think. I'm trying to be balanced, but I just want to make the idea behind the spell useful without slaughtering the caster.