Mind Blast | Reviewed by Maker | 30th Jun 2013
• In your loop trigger, check if the picked unit is magic immune to prevent further damage (and checks).
• In your loop trigger, check the ability level of the caster, so that, in case he levels this ability up, while damaging the units, the new bonus will be applied instead (since it's a matter of personal taste, you might want to use a global boolean that checks if the user would like this change in the trigger).
• I suggest improving it and further upgrading it to support stacks. This way, if a unit is struck twice by this spell, it should be dealt the additional damage, depending on the number of sources. Right now, it looks quite flat.