Ok, you want to make a new unit then. Make the model whatever you want. Give it invisibility, and whatever other stats you want on it. Now, make a shockwave spell that does nothing. Make a trigger that states:
Unit starts casting Shockwave
Create 1 Mine at [Target Point of Ability Being Cast]
Then to make the explode, make a spell that is say....Warstomp. Something that you click, and it casts. Make it do nothing also. Make a trigger for that too that does however much damage around the unit, and kills it. If you are going to make it able to damage allies too, then use the action Unit-Damage Area.
Otherwise, do a for group for all enemies around it, and do Unit-Damage Target for all of them.