Metamorphosis bug help

I modified metamorphosis and gave it to a custom hero as an ultimate. However the hero freezes instead of transforming to the unit I want, I just couldn't do anything with him. Then the game crashed to the desktop after the duration ended.

Is there any thing I missed ?

What are you changing him into? Do both the hero and the unit he is changing into have identical starting points and points per level for str/agi/int? (though this shouldn't make it crash, it's good to do) What did you set the "Normal Duration" to? It doesn't actually determine duration for a normal unit, it is the transformation time. Do both units have the same copy of the metamorphosis spell? Gimme more details.

I edited the 'Alternate Form Unit' to a wendigo, but didn't do any stats modification for it yet. So it doesn't have the metamorphosis spell.

You must select a hero in the metamorphosis spell, or else the game crashes.... so you:
- Base the wendigo of an Hero, (edit the skin)
- Give that wendigo the metaporphosis ability

And that should work.