Lol... Ok I will explain what Silver18 said.
First step : You got your skill already? The "Meteor" like skill? If not, do this steps :
a. Open Object Editor or press F6
b. Click the Units tab then press Ctrl + Shift + N
c. When you done that, a new tab and you can see in the upper right in it, the "Hero". Click it and find the Items. After that find the Inferno(Item).
d. Find the "Hero Ability" then click it. Right click it then check it, Then on the "Item Ability" uncheck it. You got your ability now!
Then the Second Step : Find the Data - Summoned unit then press Shift + Enter, erase any existing words then write "none".
Then Done! You got your very own Meteor Spell! Be sure to edit other things in it.
Well I tested it and it works. You just need to edit some data. You can also use the Inferno Abilities by DreadLords.