Short, but somewhat preoccupying questions

[NTJedi]

void said:
Note: Doom horrors you get from wish randomly disappears. It may vanish at the 3rd month you get it, or it may not disappears till the game's end. Once it's gone, you'll get a message like "Agon was suddenly nowhere to be found".

HTH

Anyone know if there's a modding command which can be assigned to newly created units which would cause this effect?
I'd like to create a hero who randomly just walks away one day.