how to make unit xplode on death?

1. if u have storm bolt and want unit xplode under its effect. (I mean generic unit, not specific)

2. or make unit xplode if hit by any spell that does 1000 damage. (also generic unit,not specific)

does these involve trigger? if so, please tell me how to do it.

for the first one, if you are just talking about adding the explosion effectart onto the target unit, you can just add the explosion art under the target art.

what i mean is, how to make unit explode when they die if attacked by a certain spell, for example FOD, if it kills the target unit explode. i wanted it to for StormBolt. anyway to do that?